Cut two pieces of 2 by 10 wood 18 inches in length. These will form the sides. Cut two pieces of 2 by 10 wood so that they measure 36 inches. These will form the interior shelves. Cut one piece of 2 by 10 wood so that it measures 38 inches long. This will form the top. Sand the cut ends of each piece of wood until it is smooth. Pay special attention to the corners. If the sides of the wood are not finished, sand these as well to make them smooth.
Mark your side pieces of wood that measure 18 inches at 6, 7 1/2, 13 1/2 and 15 inches. Lay one side piece on its lengthwise edge so that the outside is facing to your left. Lay one of your interior shelving pieces so that its end rests between your 6 inch and 7 1/2 inch markings. Using your power drill, screw the shelf in place, leaving 1/4 inch of screw exposed. The screws enter into the outside of the side piece and pierce the shelf edge. Make sure the screws are 1 inch from each edge of the side piece when they are screwed in. Repeat with the other side piece and opposite end of the shelf.
Lay another shelving piece so that it rests between your 13 1/2 and 15 inch markings on each of the side pieces. Screw in. Set up your unit so that the last 3 inches of the sides are resting on the floor. Take your 38-inch long piece and rest it on the top so that it matches up with the edges of the top of your side pieces. Drill in screws from the top of the board into the ends of your side pieces.
Slowly working up the sides and on the top, drill the outside screws that are still 1/4 inch exposed into the wood to ensure that the shelves and top are firmly secured. Insert brackets into every corner, 1 inch from the edges of the boards, and screw in place using #8 head, 1 1/2 inch deep screws.
Find a well-ventilated area or a place to paint outside that is also a dry environment. Cover the surface your cabinet will rest on with newspaper. Apply stain evenly with a paintbrush to both the outside of the cabinet as well as the shelving interior and edges, and allow to dry overnight. Alternately, apply a primer and let dry overnight before painting with your preferred color.