Measure and cut four 6-foot-long 2-by-4 inch boards. Measure and cut eight 22-inch-long 2-by-2 inch boards. Then measure and cut 12 3-foot-long 1-by-4 inch boards.
Place two of the 2-by-4 inch boards on the ground, broad side down and parallel to each other. Starting at one end, place a 2-by-2 inch board across the 2-by-4 boards so the ends of the 2-by-2 board are even with the outer edges of the 2-by-4 boards. Add 2-by-2-inch boards at 24 inches, 48 inches, and the other end of the 2-by-4-inch boards. Repeat this with the other set of 2-by-4-inch boards. You now have two uprights, which you'll attach the horizontal shelves to.
Drill a 1/8-inch pilot hole through the boards where they intersect. Insert a wood screw into the hole and screw it in to fasten the boards together.
Add 2-by-2 inch boards at 24 inches, 48 inches and at the other end of the 2-by-4 boards. Repeat this with the other set of 2-by-4 boards. You now have two uprights to which you'll attach the horizontal shelves.
Stand the two uprights up and parallel to each other. Place a 1-by-4 inch board between them, resting on the 2-by-2 inch boards and 24 inches up from the bottom. Line up the 1-by-4 board even with the outside edge of the uprights and screw it in place on each end with two wood screws. Place three more 1-by-4-inch boards between the uprights, spacing them 2 inches apart.
Place 1-by-4 inch boards on the 2-by-2 inch boards at the 48-inch mark and at the top with the same spacing as before. Screw them into place. Move the shelves to your desired location.