Place two pieces of 8-foot 2-by-4 and two pieces of 44-inch 2-by-4 on a flat surface with the 2-inch surfaces of the board on the building area in a rectangular frame (The boards will look like they are "standing up"). The shorter pieces should fit in between the longer pieces and be pushed to opposite ends to form a 4-foot by 8-foot frame. Screw the frame together by driving two 3-inch screws which are in a vertical line though the 8-foot pieces into the sides of the smaller pieces.
Measure 4 feet along one of the longer ends of the frame to find the center and make a mark. Place another piece of 44 inch 2-by-4 inside the frame with the 2-inch side pointing down (same orientation as the frame) at this point for a cross beam. Screw this piece to the frame by driving 3-inch screws through the long side of the frame and into the cross beam.
Place a piece of 4-foot by 8-foot plywood on top of the wooden frame. Screw the plywood to the frame by placing screws in each corner and then spaced apart around the perimeter every 6 inches. Drive each screw into the frame from the top of the plywood. You will use approximately 24 screws to screw the plywood to the frame.
Repeat this process and build five more platforms. The platforms will be connected to form the stage floor.
Turn one of your platforms over so that the plywood "top" of the platform is on the building surface. Place a piece of 2-foot 4-by-4 in the corner closest you so it is on the plywood and snug against the frame. Screw this leg into the platform by driving three 3 inch screws through the frame on each side and into the sides of the leg.
Place a 2-foot piece of 4-by-4 in each of the frame corners and screw them into the frame by driving screws into the top of the legs through the plywood. Turn the platform over so it is standing on the legs.
Repeat the process for leg installation for the other five platforms. Place them in a rectangle which is 16 feet by 12 feet and make sure that all the edges are flush.
Crawl underneath your stage. Connect the platforms together by driving a pair of 2-inch screws through the frames in a vertical line approximately 1 foot apart. Make sure all edges which touch are connected in this manner. You should now have a 2-foot high stage which is 16 feet by 12 feet.
Press the 4-inch edges of two pieces of 8-foot 2-by-4 so that the ends are even and screw them together using 2-inch screws. Repeat this process with the last two pieces of 8-foot 2-by-4.
Join the ends of the beams you just built together to form a beam which is 16 feet long Place a piece of 6-inch by 4-inch 3/4 inch plywood over the junction where the beams meet and screw the plywood to the beam to create a splice to hold the beam together. Turn the beam over and place the other piece of 6-inch by 4-inch plywood over the seam and screw it into the beam. The 16-foot beam should now be one piece. Install the curtain track on the beam according to the directions that come with your kit. Don't hang the curtain at this point.
Stand one of the pieces of 8-foot 4-by-4 on the ground next to one of the front corners of the stage so that it is about 4 inches behind the front of the stage front. Attach it to the stage with a pair of vise grips. Crawl under the stage and drill two 1-inch wide holes through the frame and the piece of 4-by-4. Place a carriage bolt in each of these holes and bolt the 4-by-4 to the stage frame. Repeat this process on the other side of the stage for the remaining 4-by-4.
Stand on the ladder and place the 16-foot beam between the two 4-by-4 posts at the top. Screw the beam to the posts by driving three screws through the 4-by-4 post from the outside into the beam on either side. Position the draw string so it is next to one of the posts.
Hang the curtain on the track. The curtain should hang down far enough to just barely touch the stage floor.