Lay one 36-inch long board flat on a work table or the floor. Set the side that you want to be on the inside of the nightstand up. Stretch the measuring tape across the length of the board. Draw a line with a pencil on the wood at the 18-inch point, stretching it across the 12-inch width of the board. Repeat with the second 36-inch board.
Set the 7-inch board on one of the 36-inch boards. Place the 7-inch board perpendicular to the 36-inch board at the point where the line you drew is located.
Turn the boards over so that the outside of the 36-inch board faces you. Drill three screws into the boards to attach the 7-inch board to the 36-inch board, spacing each screw 4 inches apart. Repeat with the second 36-inch board, making an "H" shape.
Stand up the "H" shape. Place one 9-inch board on top of the "H," lining up the 12-inch sides of the board with the 12-inch sides of the two 36-inch boards.
Drill six screws into the two sides of the 9-inch board to attach it to the 36-inch boards, using three screws on each side and spacing the screws 4 inches apart.
Turn the "H" shape upside down. Set the second 9-inch board on top of it. Attach the board to the 36-inch boards in the same manner you attached the first 9-inch board, using three screws, spaced 4 inches apart, on each side.
Paint the nightstand in your choice of color using the paintbrush. The nightstand can match or coordinate with the paint color on the bedroom walls or match the color of the bed. Let it dry overnight.