Spread the five 18-inch-long boards side by side on a flat surface running parallel to one another. Space the boards ¼ inch apart.
Lay the 1-by-2 board perpendicularly across the five boards. Adjust the board so it rests on its 2-inch width, and align it to run 1 inch in from the edge of the five boards. Insert five evenly spaced 1 ½-inch screws through the board and into each of the five boards below.
Place the 2-by-2 board to run opposite the 1-by-2 board. Bring the board 1 inch in from the other side. Secure the board with five 2 ½-inch screws.
Stand the 14-inch 2-by-12 board upright over the 1-by-2 board. Hold a piano hinge to the point where the 14-inch board meets the 1-by-2 board. Insert 1-inch screws as needed along the hinge to attach it to the boards and allow the 14-inch board to fold in over the five table top boards.
Stand the 13-inch 2-by-12 board upright, and position it over the 2-by-2 board. Align the other piano hinge to the boards, and secure the hinge with 1-inch screws.
Turn the table over and extend the 13- and 14-inch boards to rest upright. To fold the table, fold in the 14-inch leg under first, followed by the 13-inch leg.