You begin in a spa room of sorts with a massage table to your left. Turn completely around and move out of the wooden door. You should see some rocks that spell out art in a corner across from you. Go into the door to the right of those, and then move to the left of the massage table inside this new room, towards the radiator. Turn completely around once you're next to that radiator, and move into the door on the left outside of the current room. In that door you should see marble tiles. Step across to the foot of the stairs and you're done.