Place two filing cabinets side by side in the reception area. Measure between the filing cabinets and move apart until they are 36-inches apart.
Place a 1-inch thick sheet of plywood on a flat surface. Place the 1/2-inch sheet of plywood on top of the 60-inch edge. The outer edge should line up perfectly.
Place one L-shaped bracket along the top edge at each end. Attach the bracket to the plywood with two 1/2-inch screws. Position one L-shaped bracket every 12-inches across the 60-inch edge and attach with 1/2-inch screws. This will complete the securing of the L-shaped plywood structure.
Apply a large amount of construction adhesive to the tops and back sides of the filing cabinets. Set the L-shaped plywood structure on top of the filing cabinets. The 1-inch thick plywood should be positioned on top of the filing cabinets and the 1/2-inch thick plywood should be in the back. Allow glue to dry for 24 hours before using.