Remove the mattress and box spring from the metal frame.
Place the metal frame inside the wooden frame.
Attach a fender washer onto a 1 1/2- to 2-inch screw.
Stand inside the mattress frame. Place the end of the screw through the mounting hole at the bottom corner of the metal frame.
Drill the screw through the mounting hole and into the wooden frame.
Repeat Steps 3 through 5, installing screws through each of the mounting holes in each of the remaining corners of the bed.