Determine the length of your bench, and cut the 2 x 12 and 1 x 4s to this length. For the purposes of this article, we will make the bench 6 feet long.
Make a mark on the bottom edge of one 1 x 4 four inches from one end. Use the square to draw a 45-degree angle from this mark to the corner, then cut off this triangular piece. Repeat on the other end of the 1 x 4. You will now have a brace with one full-length edge and one that tapers to a shorter edge. Repeat with the other 1 x 4.
Cut a notch four inches wide in one end of each 2 x 10 leg. This will make it easier for the legs to sit level on the floor.
Assemble the two braces and legs. Using the square, draw a line perpendicular to the top of the brace that extends to the bottommost point of the taper. Use this line to ensure that one of the legs can be attached perpendicular to the brace. Apply a layer of glue to the top 3 inches of one leg, then align this leg to the line, make sure the top of the leg is level with the top of the brace. Attach the brace to the leg by driving two or three nails through the brace into the leg. Use the damp cloth to wipe off any glue that oozes out of the joint.
Repeat this procedure three more times, first attaching the second leg to this brace, then attaching the remaining brace to the assembly. When all four pieces are attached, it should appear as though the bench legs extend down from the bottom of the tapers on the braces. The structure will be very steady.
Apply a bead of glue along the top edges of the braces and the ends of the legs. Center the bench seat on top of the base unit, then drive nails through the top and into both braces and legs. Wipe off any glue that oozes out, and allow the bench to dry.
Sand the bench lightly, then apply finish with the applicator, following the manufacturer's instructions. Let it dry, and your bench is ready for use.