Place the headboard against the wall where the bed will ultimately rest. Set the side rails on the floor perpendicular to the headboard. Place the footboard against the opposite wall. Set the cross slats in between the side rails. Gather the required bolts, washers, nuts and screws and place them nearby for easy access.
Hold one side rail up to the bolt holes on the iron headboard. Insert a bolt through the headboard leg and into the corresponding hole on the side rail. Secure the bolt with a washer and nut. Tighten the nut with your fingers at this point. Repeat with any other corresponding holes on that side of the headboard. Move to the other headboard leg and side rail. Insert bolts, washers and nuts into the corresponding holes and tighten the nuts by hand.
Hold the iron footboard against one side rail. Insert bolts through the leg of the footboard into the corresponding holes on the rail. Secure them with washers and nuts. Tighten the nuts using your fingers. Repeat with the other side of the footboard, tightening the nuts by hand.
Tighten the nuts on each corner of the iron bed frame with a wrench.
Set the cross slat closest to the headboard in place, spanning the rails. Align the screw holes on the cross slat with the corresponding holes on the side rails. Use a screwdriver to tighten the screws in place on both ends.
Move to the bottom of the bed. Match up the screw holes on the cross slat to the side rail holes. Tighten the screws with a screwdriver. Repeat this process with the center cross slat.