I need to design the floorplan for an appartment, where only the living room is on a lower level (ca.70cm lower) connected with stairs to the rest of the appartment. I dont know how to design that. I couldnt manage to do it by creating a complete second floor, nor by extruding the higher part of the appartment (didnt work out with the wall heights. They were limited to 280cm). Can someone give me a hint how I can do that? See the picture, how the two levels and the stairs should look!