Fold out the cross arms on both rails so that the arms fully extend away from the rail. Lay the rails beside each other so that the cross arms point to the opposite rail.
Attach the headboard brackets to one end of both the bed rails, if you will be attaching a headboard later. The brackets attach with 7/16-inch bolts and nuts. When attaching the headrail brackets, insert the bolt through the outside and thread the nut from the inside of the bedrail. Tighten with a 7/16-inch socket wrench.
Insert the button rivets of the cross arm on the front of one rail to the keyholes on the cross arm of the opposite rail. There are three different sets of keyholes to accommodate different bed sizes. The keyholes nearest the rail will be for twin size and the keyholes farthest from the rail for king size. Pull the two rails away from each other to lock the button rivets into the keyhole slots.
Place the button rivets of the cross arms on the back of one rail to the keyhole slots on the opposite cross arm. Be sure to place the cross arms into the same keyhole slots as the first pair. Pull the rails away from each other to lock the buttons into the keyhole slots.
Place the plastic "L" caps over the back, or foot end, of each rail. This is the end opposite the end you attach the head rail mounting brackets. The plastic caps will push over the rail ends with your fingers. These caps protect you from cutting yourself on the sharp metal frame edges.
Place the caster sleeves into each open foot peg on the bed rail and insert the wheel casters into the sleeves. The metal bed frame is now ready for your box spring and mattress.