Tiny Apartment Feng Shui help.?

I live on the top story of a building in a small apartment. The bottom story is a business. My question is about Bagua. When I make my Bagua map, do I go by the entrance to my room? or by the entrance to the bottom story? They are both facing different directions. Also, Do I use my Bagua map on only my bedroom? Or on my whole apartment? Because the closet and bathroom would be taking up some important squares on my map. I probably sound really ridiculous, but I'm very interested in doing this correctly. Feel free to give me any tips. I'm a beginner. Thank you for your help! :]