So I have imported a room and I have selected the floor and walls and turned on Simple Collision for those parts. How do I test them out? I just want the floors and walls to stop a player’s movement. I don’t notice any change navigating thru the scene. 
you may have turned them on, but maybe they are not there and you have to create them in mesh editor… but if you just want to mess around you could put a ‘blocking volume’ in (block all) just to get it going…