In addition to what Doug rightly said, I believe the first step will be to rotate the image so you have the main lines (roughly, depending on the photo) vertical and horizontal including the bounding ones.
The approach will also depend on whether it is supposed to represent the appearance on the photo, which has been taken from a spot above the lower part of the roof, or represent a reproduction of the original floor plan with (many) right angles.
Nothing. I literally just got introduced to AI. I figuratievly still have my umbillical cord attached... just purchased AI. I dont even know how or where to begin.