I started with the building on the right side first. Working from the top of the building down, I put on the aluminum roof, leaving a slight ripple in the top line of the building. Finished the roof by adding in a few lightning rods.
Next, I extended the wall to fit under the roof, straightened up the barn doors, added the frame around the window and finished by putting on the barn board.

From there I started on the building on the left side, I first worked on the back attachment to the building, putting on the roof and indicating a door.
Next, I started straightening out the front part of the building, but I had to get ready go to an appointment.
I will post this drawing at a later date once it is completed.