How to determine the orientation of the house, look at the unit door or your own door?

Look at the unit door, which refers to the orientation of the building, and look at your own door, which refers to the orientation of the entrance door of the house (Feng Shui masters are very concerned about this), and the orientation of the house mainly refers to the orientation of the window. Suppose the word "day" has windows at the top and bottom, but no windows on the left and right. According to the direction of up, north, down, south, left, west, right and east, it is the north-south direction, and the entrance is either on the left or on the right.