Build a 4 foot by 8 foot rectangle out of two pieces of 7 foot 10 inch 1-by-3 and two pieces of 4 foot 1-by-3. The longer pieces will go in between the shorter pieces. Make sure all the corners are square with the carpenter's square and screw them together with the drill.
Measure four feet to the center of the frame and make a mark with a pencil. Place a piece 4-foot 1-by-3 at this location, make sure it is square and screw it into the longer sides of the frame.
Place the piece of 4 foot by 8 foot sheet of luan on top of the frame. Screw it into the frame along the perimeter of the luan. The flat is now ready to be used as a wall on stage.
Build an 8 foot by 4 foot frame out of the two pieces of 7 foot 8 inch 2-by-4 and 4 foot pieces of 2-by-4. Make sure it is square and screw it together.
Measure 4 feet along the long edge of the frame from one corner. Place the center brace (the last piece of 4 foot 2-by-4) in the center of the frame and screw it in once you have made sure it is square.
Place the piece of 4 foot by 8 foot 3/4-inch plywood on top of the frame and screw it down along the perimeter.
Place a caster in each corner of the platform you have just created on the bottom of the 2-by-4 and screw them into place.
Drill a hole through the plywood in the center of one of the shorter ends of the platform which is large enough to feed a rope through. Feed the rope through the hole and tie it to the platform. When you pull on the rope, the platform will roll.