3. Roof Line
Use the rules on vanishing points to establish another window and the first floor roof line. Draw a curve on top of this window. Sketch rectangles inside the other three windows. Draw a curve on top of this window.
Establish a wide U-shaped figure on the front plane for the entrance. Draw a door with straight lines and a rectangle inside the entrance as shown, keeping in mind that the door is on the same plane as the side of the window.