Measure your shade structure area and plan your foundation. Your shade structure will have four posts, so choose an area where each of the four corners can be dug-in and secured.
Dig a hole at each of the four corners 10 to 12 inches deep and position each of the posts vertically. Fill in the hole around the post with the dug-up ground and compress the soil to give the structure strength.
Attach 3-foot-lengths of timber, connecting each of the four posts to form a square boundary around your shaded area.
Cut 3-foot lengths of timber for the trusses. These will run across the shortest span of your shaded area at even centers, crossing the width of your frame.
Nail the trusses to the frame at no more than 2-foot centers for the length of the shade structure.
Stretch the shade cloth across the top of the shade structure and nail to the outside of the trusses at 4-inch intervals.