Cut four lengths of 2-by-2-inch lumber measuring 1-foot long. These are the legs. Cut two 1-by-3-inch boards measuring 1-foot long. These are the short supports.
Position two of the legs on a flat surface parallel to each other and 1-foot apart. Slide one of the short supports in between the two legs, flush with the top. Screw through the legs into the side support using one 3-inch wood screw on each side of the short support. This is one side of the bench, repeat to make a second side.
Cut two long supports from 1-by-3 inch lumber measuring 3 feet long. Place the two sides up on their legs. Arrange the sides so that they are directly across from each other and 3 feet apart. Place one of the long supports in between the front legs. Adjust this board so that it is even with the top of the legs, then screw in place. Repeat on the back side of the bench.
Cut two center supports measuring 16 inches long from 1-by-3-inch lumber. Position the first center support vertically between the two long sides and 1 foot away from the left end. Screw in place. Repeat on the right side of the bench.
Cut four seat slats from the 1-by-3-inch lumber measuring 40 inches long. Position the slats across the bench horizontally. The slats should each have a 1-inch space between them. Screw each slat in place.
Fill the screw holes with wood filler. Sand the entire bench with 120-grit sandpaper to remove rough edges.
Apply two coats of wood stain in your desired color and allow the bench to dry completely.