How to determine the part of the drawings where the doors and windows are located

Construction section is based on the building plan marked on the cut location and projection direction, assuming that the plumb direction of the cut plane will be cut behind the building to get the orthographic projection. Drawings are from the outside to the inside to see, windows and doors triangular line is dotted line, it proves that is open, solid line is open, the direction of the drawings for the intersection of real and imaginary lines in the right, that is open to the right, the intersection of the left that is open to the left.