Lay the 2-inch by 2-inch by 8-foot posts on an even surface. Place the 2-inch by 2-inch by 4-foot cross section board on the top of the posts. Secure the cross board by screwing long wood screws into the posts with an electric screwdriver.
Place the 2-inch by 2-inch by 3-foot 8-inch board between the posts 30 inches from the bottom. Secure the cross board with long wood screws through the posts into each end of the cross board. Attach the lattice work to the back of the frame using long staples with an electric staple gun.
Make a U-shape frame with the remaining 2-inch by 2-inch by 4-foot boards. Use the wood screws to screw the boards together. Measure 4 feet from the top of the trellis and mark the measurement on both posts with a pencil. Attach the U-shape frame to the posts with screws using the marks as guides to keep the frame level.
Staple the top of the canvas shade material to the top of the trellis. Space the staples every 2 to 3 inches apart. Stretch the canvas around the outer-most board of the U-shape frame. Fold any extra canvas under the board and staple.
Locate the trellis with the shade canvas in the desired location and drive the legs into the ground with a hammer. The legs need to be at least 24 inches deep to withstand most windstorms.