Rooms are built by mining the earth in the mountain. Your minions will do this for you, following the orders you give them in the guise of a blueprint. To begin building a room, move your cursor over a free piece of un-mined dirt. The cursor should change into something like the image on the right when you are mousing over an acceptable area. Right click where you want to start building and the list of rooms you have available to build appears on the left side of the screen. The cost for one tile of the room is also shown. Left click on the type of room you want to create. A new window will appear in the upper-left corner of the screen, detailing the specifics of the room you chose. There are two options in this window - the left cancels the blueprint and the right commissions the room.

You can now drag out your blueprint to the area you wish to create into the room. This is done by left clicking and dragging an area, or by selecting the tiles one by one. Make sure that the room is connected to a corridor or another room. There are some simple rules about how to design a blueprint. First off, you cannot dig in solid rock. You can also not split up the blueprint in 2 separate pieces. If you would like to add another room of the same type, you first need to finish the first room and then you can proceed by creating a blueprint for the second room, following the same procedure. You can also not make a 1-tile wide corridor, at least not in a straight line. A tile must have at least 2 tiles beside it which are not opposite of each other, which means it IS possible to create a 1 tile-wide corridor in the shape of a stair.