Cut and sew your drapery material with 6-inch hems. Make the drapes in two sections so the curtain will part in the middle to allow actors to enter the action. Use enough material to allow the drapery to pleat when the back wall is covered. Make sure the material is long enough to reach the stage floor when hung.
Slide the top curtain hem onto a piece of 3-inch PVC pipe that is long enough to stretch across the back wall of your stage. The plumbing supply company where you buy the pipe can cut the pipe to the length you want. Pull the material away from the ends of the pipe so you can insert and glue pipe corner fittings.
Brush rubber cement onto the pipe ends. Insert the pipe ends into the pipe corner fittings. Make sure the corners have a 90 degree turn and that the turn is downward so you can attach pipes for upright supports.
Glue lengths of 3 inch PVC pipe into the corner fittings. These will serve as your upright supports. Ask the plumbing supply company to cut the pipe to the lengths you need to stand at the back of your stage.
Glue PVC end caps onto the bottom of your upright supports. These will help the curtain frame stand up and offer stability.
Stand the entire PVC/drapery structure at the back of your stage. Leave a walkway of about 3 feet so actors can pass behind the curtain without disturbing it during a performance. Arrange the drapery so that there is an opening in the middle of the backdrop. This will allow actors to enter the stage.