Measure the dimensions of the workbench top on a sheet of 3/4-inch plywood with a tape measure and straight edge and draw it with a pencil. A typical workbench top is about 2 by 3 feet, but you can make it any size you wish. Cut the bench top from the plywood with a circular saw.
Spread construction adhesive on the back of a length of maple flooring that is long enough to extend over the ends of the plywood by 1/2 inch or more. Lay it on one edge of the plywood so the groove-end of the board extends over the edge by 1/2 inch. Be sure the edge of the flooring board is straight with respect to the edge of the plywood and press the board down.
Clamp the board to the plywood with three C-clamps. Place one clamp within 3 inches of either end and place the third clamp in the middle. Leave the board clamped overnight to give the glue plenty of time to set, then remove the clamps before proceeding.
Spread glue on the bottom of a second length of flooring as long as the first one and tap the grooved end into the tongue of the one that is glued to the plywood. Drill 5 or 6 evenly spaced pilot holes in the tongue of the second board so that you can nail it down. Snip the head off of a 1-inch finish nail and use the nail as a bit. Drive a 1-inch finish nail into each hole with a hammer and sink the head with a nail punch.
Continue laying flooring on the plywood in this way, spreading glue on each board and nailing it in place, until you reach the opposite side. When you install the last board, clamp it as you did the first board instead of nailing it and leave it clamped overnight.
Turn the bench top over so that the plywood is facing up and trim the flooring flush with the edge of the plywood with a circular saw.
Sand the edges of the bench top with an orbital sander and 100-grit sandpaper until they are smooth and slightly rounded. The surface of the bench top should be flat, but there may be slight variations. If so, sand them flat with the sander.