Alright, so according to the numerous demands to explain TableTop Simulator, I decided to hop into the virtual tables and take screenshots of how I do things.
Here you will see how you can hide things from the players in a very easy way using ''black cards''. You need to upload a black rectangle, or black square into IMGUR.com. Then, you create a custom object (a play-card) that has the URL for that image. It then gives you a totally flat and totally black card.
Then, you can copy-paste all around to cover the elevations and what is inside the dungeon. That means, you can leave all your mini figures and monsters in there, and cover everything up. Just press DELETE on each card when the heroes can see further, accordingly to the player's progression. Fog of War also has a very similar function. You can increase and decrease the size of either ''card'', or ''fog of war''. I prefer using a big black card, it is easier to manipulate and move around the table and you can rotate it on 360 degrees to cover horizontal and vertical spots. The card will remain totally flat and cover elevations, caverns, walls, passages, and so on.
In Demonstration no.4, I explain the whole process of the MEMORY BAGS for HeroQuest, (or any DnD game). Stay tuned.