Lay two 25-inch boards flat, parallel and 45 inches apart. Set two 45-inch boards between them at right angles and spaced 22 inches apart. Set a 48-inch beadboard sheet on top of the boards so the edges are flush. Screw the beadboard to the boards using four screws for each 45-inch board and two screws for each 25-inch board. This is the front side of your beadboard panel chest. Repeat this step to create the back side.
Position the sides upright, parallel, so the boards are between the paneling. Space the sides so the outside of the beadboard is 24 inches apart. Screw the 24-inch beadboard sheets to the 25-inch boards on the sides so the corners on the chest frame are flush. Use eight screws for each sheet.
Lay your plywood on top of the frame so the edges are flush and screw it to the 45-inch boards using eight screws for each board. This is the bottom of your chest.
Turn the chest over and screw a pair of half hinges to the top edge of one 45-inch board. Position each hinge 9 inches away from the ends of the chest so they can fold up, out and around the outside of the chest.
Screw the other half hinges to the 49-inch beadboard sheet so it can open up away from the chest. This is the lid to your chest. When the lid closes, its edges will be flush with the sides of the chest.
Position a corner trim over each corner and hammer them to the chest so the ends are flush with the top and bottom of the chest. Use four nails for each piece. Pound the nails through the corners at a 45-degree angle.