Build the frame of the panel by using the 2-inch by 2-inch by 6-foot boards as the sides. Nail a 2-inch by 2-inch by 3-foot board flush across the top of the long boards to connect them. Continue nailing the 3-foot boards to connect the 6-foot boards every 1½-feet. This should give you 1-foot legs on either side.
Lay the frame flat on the floor. Place the plywood panel on top of the frame and align it so the plywood is aligned with the top of the frame. There will now be 6 inches of legs extending from either side of the frame. Secure the plywood in place by nailing it down. It should now resemble a panel.
Drape the carpet over the panel so it overlaps evenly on all of the sides; about 3 inches per side. Staple the carpet down by folding the carpet over the edges and stapling it to the back of the panel. No staples should be visible on the front of the board. Work your way from the top back of the panel down both sides of the panel. Stop right before the legs.
Cut a slit in the carpet on the inside of each leg up to the plywood sheet so that you can easily fold the carpet to the backside between the legs. Staple the carpet to the back of the plywood between the legs, then staple the carpet to the front of the legs. Use only one staple per leg so there are not too many staples showing on the front of the legs.
Move the umbrella stands near the panel and fill the umbrella stands with as much sand as possible to add weight.
Stand the panel upright and place each leg in the adjustable umbrella stands. Tighten the pole openings so that they securely hold the panel upright.