Place the two pieces of 18-by-30-by-3/4-inch plywood on a work table. Measure from one 18-inch edge and make marks at 4, 4 3/4, 15 and 15 3/4 inches. Place the framing square on the marks and draw lines across the plywood.
Drill three pilot holes with the 1/16-inch drill bit between the lines. Make one of them 1 inch from the long edges and the third in the middle between the two. Apply glue to the18-inch edges of the two pieces of 18-by-22 1/2-by-3/4-inch plywood. Secure them between the lines drawn on the sides with the finish nails. Clean up excess glue with a damp cloth.
Put some glue on the 4-inch edges of the 22 1/2-by-4-by-3/4-inch plywood. Secure it between the sides at the top. Make the 4-inch wide side of the plywood even with the long edge of the sides of the bottom of the hutch.
Set the two pieces of 12-by-42-by-3/4-inch plywood on the worktable. Measure from one of the 12-inch edges and make marks at 12 3/4, 13 1/2, 25 1/2 and 26 1/4 inches. Mark the edge from which you measured as the top of the sides to the top section of the hutch. Draw lines across the plywood as before and then drill pilot holes in the same manner.
Apply glue to the 12-inch edges of the 22 1/2-by-12-by-3/4-inch plywood. Set them between the lines drawn on the sides of the top of the hutch and at the top as well and secure them with the finish nails. Clean up the excess glue with a damp cloth.
Glue the 2-inch edges of the 22 1/2-by-2-by-3/4-inch plywood. Secure it between the sides and at the bottom of the top section of the hutch with the finish nails. Make the 2-inch edge even with the 42-inch edge of the sides.
Stand the top section of the hutch on its top. Apply glue to the 12-inch edges of the sides and set the 24-by-19-by-3/4-inch plywood on the glue. Secure it through the 24-by-19-by-3/4-inch plywood into the sides of the top section of the hutch with the finish nails.
Turn the top section of the hutch upright along with the bottom section. Apply glue to the top edges of the bottom section of the hutch. Place the top section on it and secure it to the bottom section through the 24-by-19-by-3/4-inch plywood with the finish nails. Secure the 24-by-68-by-1/4-inch plywood to the back of the hutch with the box nails.