Place the 3/4-inch plywood onto a work bench or on top of saw horses and measure out 40-inches by 14-inches, marking the measurements with a pencil.
Put on safety glasses and a dust mask. Cut the plywood to 40-inches by 14-inches with a circular saw. Set this piece aside as the sideboard table's top.
Measure the four 2-inch by 2-inch lumber beams to cut down to 30-inches long. Cut the four 2-inch by 2-inch lumber beams to 30-inches long with your circular saw to create the table's legs.
Measure and cut two of the four 1-inch by 3-inch lumber beams to 10-inches long to form the side skirts. Then measure and cut the other two 1-inch by 3-inch lumber beams to 36-inches to form the front and back skirts. Set these aside.
Set the 40-inch by 14-inch cut plywood on to the floor. Place the legs at each corner.
Fasten the 10-inch skirts to the 36-inch skirts with a nail gun, forming a rectangle. Then, fasten the skirt to the plywood table top with a nail gun. Insert the legs into the inside corners of the skirt and fasten with your nail gun. Stand the table upright.
Sand the entire sideboard table and then paint or stain with a paint or stain of your choosing. Let dry for 6- to 8-hours before using your new sideboard table.