Measure the width of the window that will receive the valance. Cut a piece of plywood to the width measurement plus 6 inches with a height of 12 inches with the saw.
Cut two pieces of plywood to measure 12-inches by 6-inches for the sides of the valance.
Glue the wood pieces together with one shorter piece on each side to create an open rectangle with a missing long side. Let the glue dry for 3 hours. Pound in the penny nails at the joins with the hammer, adding a nail every 3 inches along the join.
Cut the birch bark sheets to fit the valance frame with the saw. Attach the birch bark to the valance with the hot glue gun.
Hammer picture hangers into the top side back corners of the completed birch bark valance to assist in hanging it up.