Place the cabinet in a work area. Adjust the fence on the circular saw to make a 5-inch wide cut. Turn the cabinet upside down so that the base is upright and vertical. Saw around perimeter of the base with the fence riding along the edge of the cabinet bottom to cut 5 inches off the bottom of the cabinet. This will bring the cabinet down to an approximate height of 30 inches depending on your specific cabinet height. Make sure the cut will not interfere with the door of the cabinet. If the cut falls in line with the door, you can remove the door by unscrewing the hinges. The space inside will still be functional without a door.
Sand the existing finish on the cabinet so that new paint can be applied. The shine from the existing must be removed for a new finish to adhere properly. Sand the cut edges around the bottom of the cabinet until they are smooth.
Screw one floor leveler into each corner of the bottom of the cabinet. The floor levelers will protect the floor surface and allow the cabinet to sit flat on a floor to create a level desk base.
Measure the cabinet dimensions. Mark the measurements on a paper for reference.
Measure and cut the plywood panel so that it will hang 6 inches over each side of the cabinet,1 inch past the back and 12 inches past the front of the cabinet. Use a table saw to cut the plywood panel to size.
Sand the edges of the plywood panel until they are completely smooth. Apply edge banding to the edges of the plywood using an iron to secure it in place.
Trim the banding with an edge banding trimmer so that it is flush with the top and bottom surfaces of the plywood panel. The plywood panel is the desk surface.
Align the desk surface on top of the cabinet so that the overhang is even on the sides and back of the desk. The front of the desk will overhang 12 inches to provide leg room underneath the desk. Drive flush trim wood screws evenly spaced every 6 inches through the plywood panel into the top edges of the cabinet using a screw gun.
Install a shelf bracket 1 to 2 inches in from each side under the 12-inch overhang using the provided screws and a screw gun. This will support the overhang.
Fill the screw holes with wood putty using a putty knife. Allow the putty to dry. Sand the putty flush with the surface of the wood.
Paint the base and desk surface. Allow the finish to dry. Move the desk into place in the room.
Adjust the floor levelers so that the desk sits level on the floor by turning the feet on the leveler. Verify that the desk is level by placing a level across the work surface.