Position the Lewis headboard in an upright position and line up the metal bed frame in front of it so the faceplates face it.
Line the slots in the faceplates on the bed frame up with the three pre-drilled holes on the Lewis headboard.
Thread each of the six Allen bolts -- three for the left side and three for the right -- through a lock washer.
Hold a flat washer up to one of the holes on the bed frame and insert the Allen bolt through, so it extends through the hole on the bed frame into the hole on the Lewis headboard. Tighten the Allen bolt with an Allen key. Repeat this process with the remaining five Allen bolts.