Well.. I'd suggest getting some copies of both the official and unofficial command references for starters....
But... to answer a couple of your questions
to have an AI guy sit down or something.. you'll need to use:
unitname playmove "
nameofmove"
where the unitname is the one you give it in the editor and the nameofmove is one of the animations listed in the unofficial command ref
to move guys/objects in the air.. use this in their init field:
this setpos [getpos this select 0, getpos this select 1,x]
where x = height above ground in meters...
if your building is enterable then you can create an AI unit.. give him a waypoint directly on the building name that appears in the editor.. there should be a new selection called position # or somesuch.. those positions are some of the spots inside where the AI will walk to and hold