Place the upholstered headboard behind the bed frame. Have a partner hold the headboard in place while you work.
Remove the mattress and box springs from the bed frame. Place them in an area that is out of the way.
Line up the headboard with the bolt holes in the bed frame.
Drill holes in the legs of the upholstered headboard if the headboard is handmade. While the headboard is lined up with the bed frame, mark the bolt holes on the legs. Use a drill and drill bit to drill the holes.
Slide the bolts into both the headboard leg and the bed frame. If the bolts are permanently attached to the headboard, simply slide the bed frame over the bolts.
Place a washer over the end of each bolt. Thread the nuts over the bolts and tighten with a wrench.
Move to the other side of the headboard and repeat. Adjust the bed frame and headboard to where you want them. Place the mattress and box spring back into place.