I'm unsure about how the bagua map works. If looking at our whole house, our bedroom would be wealth, the left corner of that room being the strongest area of wealth? If looking at that room with the whole bagua map then a different corner of the room falls into the wealth category. Am I looking at this the right way? Is is better to use the bagua map with the whole house, or for each room? or does it not matter?
To my knowledge, you approach each room individually *and then* approach the house as a whole unit. Remember that some things cannot be changed, and for those you will have to use other methods of feng shui to overcome, or decrease the effect of, the "bad" aspects. The primary entrance into a room is the entrance from which you figure out the baguas of the room, just as the primary entrance into the home allows you to figure out the baguas of your home.
Looking at it that way, it seems appropriate that the bottom 3 baguas (which are the ones which correspond with entrances) should be the concentration point for anyone who is beginning TMing since any kind of "baggage" or "clutter" in these areas will effect the chi of the rest of the map... hmm.