Switches are easy once you get the hang of them. First, take a sector which you want to be the switch. It should be a little higher than the surrounding floor. Then, for the door, make a sector with one side attached to the room sector, with its floor AND ceiling height BOTH equal to the floor height of the room sector (i.e. if the room sector is 1024 fracunits high, the floor and ceiling of the new sector should BOTH be 1024 fracunits. Then, as the sector effect for the button, use one of the "button for door" effects. Give the sector with equal floor and ceiling height a sector tag equal to the number of the "button for door" effect (i.e. if it was "button for door 700" the sector should have a tag of 700. Nothing else should have this tag.) Then, give the button a sector tag of one more than the previous sector (i.e. if it was "button for door 700" then make it a tag of 701. Now test your creation, and the button, when stepped on, should sink into the ground and make the sector with equal floor and ceiling height raise the ceiling to the height of the room sector. Voila! A perfect button!