Set the plywood up straight against a wall. Hold the metal bed rail up against it to see where the bolt holes align. Mark the places with a pencil on both the right and left sides of the plywood. Use a drill to punch pilot holes through the plywood to prepare to install the bed rail bolts later.
Lay the batting flat on the ground. Set the foam on top, in the center. Set the plywood on top of the foam.
Pull the batting up and around to the plywood top, keeping it tight but not enough to tear it. Staple the batting to the plywood. Move to the opposite side of the first staple and pull the batting up there, then staple it.
Work your way around the headboard, pulling up batting and stapling it so it is tight, securing the foam to the plywood.
Lay the fabric face down on the floor, so the finished side is down. Place the covered plywood batting-side down in the center.
Pull up the fabric around to the plywood side. Tuck the end under so it looks neat. Make sure there is enough tension that the fabric pulls straight, without any wrinkles or puckers. Staple it in place. Continue around the headboard, stapling two to three inches apart. At the corners, fold the fabric pleat-style and staple into place.
Alternate pulling and stapling on opposite ends of the headboard to keep the fabric taut as you work. Trim any excess material from the back of the headboard as needed.
Lay the headboard flat on the ground, with the fabric side up. Lay a piece of butcher paper over the top and mark out the tufting pattern on the headboard. Remember that the bottom part of the headboard will be behind the mattress, so only work with the space that exceeds 30 inches from the bottom.
Remove the paper, noting the first spot for an upholstery tack. Press the tack through the fabric, batting and foam, into the plywood. Tap the upholstery tack firmly into place with a hammer until the base of the tack is as close to the plywood layer as poosible. Replace the paper to get the next marking, remove it and insert another tack. Continue until the heaboard is completely tufted.
Set the headboard up against the wall where it will reside permanently. Hold one metal bed rail up against it and align the bolt holes. Screw a bolt through the rail and the headboard, securing it with a nut. Repeat with the other bolt, then move to the other side of the headboard and repeat. Assemble the crossarm on the metal rails, then put the box spring and mattress in place.