Hi,
Thank you for your post. When you set up the orientation of the feng shui for your home you want to base it upon the door that the builders intended as the front door. Regardless if you use a side door (you still can if it is better for you) the door that was intended as the front door by the architect, builders, etc, that is how you want to gage the feng shui of your home.
Give us a call here at Learning Strategies with any particular questions.
All the best!
Kat