Determine the building codes for your area that describe the depth that you need to have for your support posts. You will need to cut the support posts to this height and add 4 feet.
Dig four holes as per the depth required by codes, and space them 45 inches apart from the center in the front and 21 inches from the front two posts for the sides.
Add about 4 inches of crushed gravel into the bottom of the holes for drainage. Place the posts into the holes and fill the dirt around the posts, tamping down the dirt tightly.
Cut two of the 2-inch-by-4-inch lumber pieces to 41 inches in length. Cut three of the 2-by-4s to 21 inches in length. Cut four of the 2-by-4s to 48 inches in length. These pieces will be the flooring.
Use the tape measure to measure 6 inches from the ground and mark this line. Attach one of the 41-inch 2-by-4 in between the two front posts, and repeat for the two back posts. At each attaching point, use two screws in the top of the piece and the bottom of the piece you are attaching, through the posts.
Attach the 21-inch pieces to the inside corners of one side, and repeat for the other side. Again, use two screws to secure the joint. Attach the third 21-inch piece centered between the front and back 41-inch pieces, using two screws to secure each joint. You will now have the floor braces.
Attach the four 48-inch pieces to the braces, making sure to secure each end with two screws. You will need to use the hand saw to cut notches in two of the pieces to fit around the posts in the corners.
Cut the lattice sheets into three pieces. Two pieces should be 24 inches by 42 inches, and the third should be 48 inches by 42 inches.
Attach the larger lattice section to the front two posts using the finishing nails. Attach the smaller lattice section to the sides using the finishing nails.
Cut two of the 1-by-4 boards to a 50-inch length and two more boards to a 42-inch length. Cut a 45-degree angle at each end of the boards.
Attach the two long pieces across the top of the lattice in the front, nailing it to the posts. Attach the short pieces along the sides of the lattice in the same manner. You should now have a rectangle that frames the lattice panel.
Cut four 1-by-4 boards to 42 inches long and four more pieces to 25 inches long. Add the same 45-degree angles as before. Attach two long pieces to the top and bottom of the lattice on the sides, nail into place, and then add the four short pieces to the sides. You will now have a rectangle frame for the side lattice panels.