Measure the dimensions of the truck bed. The firewood rack should be constructed in the truck bed perpendicular to the tire humps and from the front of the bed to the back. Deduct from the measurement of the bed to allow for any toolbox that might be installed.
Measure the distance between the top of the truck bed to the bottom of the back windshield glass. For safety reasons, the wood rack should not extend past the bottom of the back glass of the truck.
Cut the 2-by-4s to the measured length in Step 2.
Cut the plywood to the length measured in Step 1, accounting for the toolbox, if it's installed.
Secure one end of the L-bracket to each of the four corners on the sheet of plywood with two wood screws and the cordless screwdriver. Secure the other end to each of the 2-by-4s, also with two wood screws.
Lift the finished firewood rack onto the truck bed and drive to the site to collect the firewood for hauling. Stack the firewood evenly across the wood rack from left to right, using longer pieces of firewood at the beginning of each row to prevent wood from falling off the rack as you travel.