If your main door is facing North direction, than it's called as North facing Main door. So if your main door is on the north wall it'll be called as entrance in North.
If you are coming out of your main door, facing North direction it'll be called as North direction main door.
From below image, it'll be clear to you. There is a road in the North direction and if your main door is facing the road, it'll be North facing main door. Hope it's clear now.