Set four 1/2-by-18-by-32-inch boards in the formation of a square, with each board standing up on its long, thin side. Adjust the relative positioning of the boards so that each board has one end touching the side of another board in a square pattern, and all spacings are equal.
Use a drill and a drill bit with a diameter that is slightly smaller than the wood screws to drill three holes into each joint. Pass the drill bit through the outside of one board and into the end of another, repeating for each joint. Pass three 2-inch wood screws through the holes in each joint and attach the boards together by tightening the screws completely with the drill. Stop tightening when the outer surface of the screw head becomes even with the surface of the wood.
Lower a 1/2-by-32 1/2-by-32 1/2-inch board on top of the other boards. Move the board slightly so that each of its edges line up evenly with the outer edges of the assembled boards.
Drill a series of holes through the top of the new board and into the sides of the assembled boards, spacing the holes every 8 inches around the perimeter. Set a 2-inch wood screw into each previously made hole, and use the drill to tighten them thoroughly. Flip the bin upside down so the open end is facing upward. Fill with firewood to dry and warm.