Mark an "X" on one face of the 1/2-inch plywood using the chalk line. Hold the end of the chalk line at one corner and stretch it to the opposite diagonal corner. Snap the line and repeat with the remaining two corners.
Measure and mark 1-inch and 4-inch from each corner towards the center. Place the tape measure along the "X" you created to find a straight measurement.
Apply wood glue to the top of each wood baluster and place one between each 1-inch and 4-inch mark. Line the outer edges of the baluster to each mark and allow wood glue to dry.
Flip the bench over and set it on all four legs on a flat surface. Screw two 3-inch screws into each leg using the drill.
Lay the 1-inch solid wood on a flat surface. Turn the bench upside down and place it on top of the solid wood.
Line up all four edges and hammer one 1-inch nail every 6-inches along the perimeter of the plywood. Place one 1-inch nail every 12-inches along the interior area of the 1/2-inch plywood.
Flip the bench over and use.