From the Wiki page on Layers : The GM Info Layer can only be seen by the GM. It's a great place to put drawings or text to remind you of traps or other information about the map that only the GM should see. You can also move tokens to this layer to hide them from players. It's like a private layer, only usable by and seeable by the GM. If you have a bunch of tokens lying in ambush, or a demon that might be summoned later, you can hide them on the dm layer. During the game, to make them appear to the players, you switch yourself to the GM layer, select the tokens and right-click. On the popup menu, select Layer > Objects and Tokens. They will be moved to that layer (you need to return, too), and the players can see them normally. You can also do the same thing, but move objects to the maps layer. This would be useful for something like revealing a pit trap.