Quick Answer: To prep a VTT session as a dungeon master, configure your maps and scenes before the session starts, assign tokens to all player characters and key NPCs, set up fog of war or dynamic lighting on encounter maps, pre-load any music or ambient sound, and test the full session from a player perspective before your group joins. The biggest time saver is building a reusable session template so setup time decreases with every campaign you run.
Running games on a virtual tabletop is a different skill set from running games at a physical table. The storytelling, pacing, and improvisation are the same. The prep work is not. A VTT session that runs smoothly is almost entirely the result of setup that happened before the first player logged in.
Here is the practical prep framework that experienced VTT dungeon masters use, covering maps, tokens, lighting, session flow, and the habits that make each session faster to prep than the last.
Why VTT Prep Is Different From In-Person Prep
In-person prep centers on notes, encounters, and narrative. VTT prep adds a technical layer on top of that. Before a single dice roll happens, you need scenes configured, maps imported and grid-aligned, tokens placed, lighting set, and connection tested across every device your players use.
The good news is that most of this work front-loads into the first few sessions of a campaign. After that, reusable assets, saved scenes, and established templates mean each subsequent session takes a fraction of the time to prepare. According to Black Lantern Forge, dungeon masters who invest in proper session one setup report that sessions two through ten take less than half the prep time of the first.
Step 1: Plan Your Scene List Before Opening Your VTT
The most effective VTT prep starts away from the computer. Before opening Foundry VTT, Roll20, or Owlbear Rodeo, write a simple list of every location your players might visit in the session.
Be realistic about which locations need a battle map and which do not. Not every scene requires a grid. A conversation in a throne room, a travel montage between cities, and a dream sequence are all moments where a static illustration or a blank scene with ambient sound works better than a tactical battle map. Save your map prep time for encounters where positioning, terrain, and movement matter.
For a typical three to four hour session, two to four fully configured battle map scenes is a reasonable target. Anything beyond that is usually prep that never gets used.
Step 2: Import and Configure Maps Before Session Day
Map configuration is the most time-intensive part of VTT prep and the part most likely to be rushed if left to the last minute. Import your maps, align the grid, and test the scene at least one day before your session.
For Foundry VTT, set scene dimensions to match your image file exactly, set grid size by dividing image width by grid square count, and confirm the grid aligns with the map artwork before placing a single token. For Roll20, configure page dimensions to match your grid count, place the map image on the Map layer, and check alignment in the page settings.
Always use the gridless version of your map in any VTT. The platform draws its own grid, and importing a gridded file creates a double-grid problem that cannot be fixed during a session without significant disruption.
The Dark Encounter Battle Maps Pack and the Shadows Beneath the Tavern Map Pack are both built at 4096 x 4096 pixels on a 30x30 grid, which means the configuration values are identical across every map in both packs. Set it up once and every subsequent import takes under two minutes.
Step 3: Prepare Tokens for Every Creature in the Session
Tokens are the single most visible signal of how prepared a DM is. Players who see a fully configured token with the correct image, name, and hit point bar feel a different level of immersion than players who see a generic placeholder icon labeled "Monster 3."
Before each session, prepare tokens for every creature your players are likely to encounter. This includes player character tokens, named NPCs, and all combat encounters. Set the hit point bar to the creature's maximum HP. Set the name field to match what players will see during combat.
For player character tokens, ask your players to provide a token image before the campaign starts and keep them saved in your asset library. You will place these tokens in every scene without needing to reconfigure them each time.
For monsters and NPCs, most VTTs have built-in token libraries or support community token packs. Foundry VTT in particular has extensive community modules with pre-built tokens for standard monster types from the official rulebooks.
Step 4: Set Up Fog of War Before Every Encounter Scene
Fog of war is one of the most impactful tools a VTT dungeon master has, and one of the most commonly skipped during prep because it takes time to configure. A session run with full fog of war feels fundamentally different from one run with a fully revealed map. Players make decisions, explore cautiously, and genuinely do not know what is around the next corner.
The level of fog of war setup you can do depends on your platform and account tier. On Foundry VTT, dynamic lighting with wall placement is the most powerful option and reveals areas in real time as tokens move. On Roll20 Pro, dynamic lighting works the same way. On free tiers of both platforms, the manual fog of war brush gives you reveal control during the session.
For encounter-heavy sessions, draw walls on your most important battle maps during the same prep session where you import and configure them. For a standard dungeon map with five to eight rooms, wall placement takes ten to fifteen minutes. That investment pays off every time those maps are used.
Step 5: Pre-Load Music and Ambient Sound
Ambient sound and music are the fastest way to set tone at the start of a VTT session. A dungeon corridor with a low rumbling ambience and distant dripping water hits differently than the same map in silence.
Most VTTs support audio through playlists configured before the session. Foundry VTT has a built-in playlist system where you can set ambient tracks to play automatically when a scene activates. Roll20 supports background music through its jukebox feature.
Build a simple library of three to five tracks per environment type: dungeon, tavern, wilderness, urban, combat. Assign the appropriate track to each scene and it will start automatically when players enter the encounter. The whole library takes one session to build and then runs itself from that point forward.
For tavern scenes, a warm background track paired with the Gilded Mug Tavern or Velvet Crown layouts from the Shadows Beneath the Tavern Map Pack sets the social encounter tone before a word of dialogue is spoken.
Step 6: Build a Pre-Session Checklist
The most consistent VTT dungeon masters use a short checklist before every session. Not a complex document, just a quick scan of the five things most likely to cause problems if skipped.
A practical pre-session checklist looks like this:
All encounter scenes are imported, grid-aligned, and tested. Player character tokens are placed in the starting scene. Hit point bars are set on all creature tokens. Fog of war is active on all encounter maps. Music playlists are assigned to scenes. A test connection has been run from a player perspective to confirm everything loads correctly.
Running through this list takes five minutes. Skipping it and discovering a misaligned grid or a missing token after your players have joined takes longer and interrupts the session.
Step 7: Test From the Player Perspective
This is the step most dungeon masters skip and the one that catches the most problems.
Before your players join, open the campaign as a player and look at exactly what they will see. Check that the starting scene is active. Check that the view is centered correctly. Check that fog of war is working and no restricted areas are accidentally revealed. Move a player token and confirm the grid snaps correctly.
Foundry VTT has a Toggle Player View button in the scene toolbar that switches your perspective to a player-level view without requiring a second device. Roll20 lets you open the campaign in a second browser window logged out of the GM account to see the player view directly.
Two minutes in the player view before the session catches ninety percent of the issues that would otherwise surface mid-session.
Building a Reusable Campaign Template
The long-term goal of VTT prep is to build a campaign template that makes each new session faster than the last.
A campaign template is a pre-configured game file with your player character tokens already placed and configured, your standard asset folders organized, your preferred lighting and fog of war settings saved as defaults, and your music library already loaded and tagged. When you start prep for a new session, you open this template, import the maps for that specific session, and the foundational work is already done.
Building the template takes one full prep session at the start of a campaign. After that, individual session prep time drops significantly because you are only configuring the maps and encounters specific to that session, not rebuilding the foundation each time.
The Prep Mindset That Makes VTT Work
The dungeon masters who run the smoothest VTT sessions are not the ones who prep the most. They are the ones who prep the right things and have a clear sense of which preparation produces the best return during play.
Map configuration and token setup are high-return prep. Players interact with these every minute of a session, and poor setup creates friction at every interaction. Elaborate NPC backstories written in your notes that never come up are low-return prep.
Invest in the technical layer early, build reusable systems, and the creative prep that actually drives your campaign gets more time, not less.
If you are building your map library for a new campaign, the Dark Encounter Battle Maps Pack covers outdoor and dungeon encounters across 10 environments, and the Shadows Beneath the Tavern Map Pack covers urban and interior sessions with two full taverns, hidden tunnels, ritual chambers, and a market district. Both are 4096 x 4096 pixels, 30x30 grid, instant download, and configured identically so your campaign template settings apply to every map in both packs.
Both packs are $14.99 with lifetime access.
Frequently Asked Questions
How long should VTT session prep take for a dungeon master?
A typical VTT session for an established campaign should take one to two hours of prep time once a campaign template is in place. The first session of a new campaign takes longer, usually two to four hours, because player tokens, asset libraries, and baseline scene settings are being configured for the first time. According to Black Lantern Forge, dungeon masters who build a reusable template in session one consistently report that subsequent sessions take half the prep time.
What is the most important thing to prep before a VTT session?
Map configuration is the highest-priority prep for a VTT session. A misaligned grid, missing fog of war, or incorrectly layered map image creates friction for every player at every point in the encounter. Token setup is the second priority. Music and ambient sound, while impactful, can be added or adjusted during the session without disrupting play.
How do I speed up VTT session prep?
The fastest way to speed up VTT session prep is to build a reusable campaign template with player tokens, asset folders, and default scene settings pre-configured. Use map packs built to a consistent pixel and grid standard so configuration values never change between maps. The Dark Encounter Battle Maps Pack and Shadows Beneath the Tavern Map Pack from Black Lantern Forge use identical 4096 x 4096 pixel, 30x30 grid settings across every file for this reason.
Should every VTT scene have a battle map?
No. Not every scene in a VTT session requires a battle map. Social encounters, travel sequences, and narrative moments often work better with a static illustration, a blank scene with ambient sound, or no visual at all. Battle maps are most valuable for combat encounters and exploration sequences where positioning and terrain actively affect gameplay decisions.
What is dynamic lighting and do I need it for VTT sessions?
Dynamic lighting is a VTT feature that automatically reveals map areas based on each token's line of sight and blocks vision behind walls. It creates a fog of war effect that updates in real time as tokens move. Dynamic lighting requires a Pro account on Roll20 and is available natively in Foundry VTT. It significantly improves player immersion but is not required to run effective VTT sessions. Manual fog of war tools available on free account tiers provide similar control with more hands-on management during play.
How do I test my VTT session before players join?
Open the campaign from a player perspective before your session starts. In Foundry VTT, use the Toggle Player View button in the scene toolbar. In Roll20, open the campaign in a second browser window without GM access. Check that the starting scene is active, fog of war is working, tokens are placed correctly, and the grid aligns with the map artwork. This test takes five minutes and catches the majority of issues before they affect your session.
