Position the two 60-inch boards on their 1-by-60-inch edges, parallel and 31 inches apart. Set the two 31-inch boards perpendicularly between them so they are also on edge and spaced 58 inches apart. Screw through the 60-inch boards and into the 31-inch boards. Use three screws for each corner that are spaced 3 inches apart. You will have a 33-by-60-inch frame.
Set the four 2-by-2-by-30-inch boards inside each corner of your craft table frame. The boards should be positioned on end, so their ends are all flush with one side of the table. Screw through the frame and into the four boards so they are secured. Use six screws for each corner so they're spaced 3 inches apart.
Position your craft table upright and lay your plywood on top of the 1-by-8-inch boards. The edges of the plywood should be flush with the sides of the boards. Screw through the plywood using five screws for the 60-inch sides and four screws for the 33-inch sides.