Visit your local Dunn Lumber yard and have them cut a piece of 1/2" plywood to size. We recommend you use CDX or ACX plywood. Regardless of which you choose, make sure it's a flat piece. Your local Dunn Lumber yard will let you hand-pick your plywood. We made a king headboard, so we had ours cut to 78" x 35." You can customize this headboard to your heart's desire. We liked the clean lines for our bedroom, so we kept it simple, but if you have access to a jigsaw you can create some visual interest by rounding the corners.
Cut your foam layer (or have it cut for you). We partnered with the Friendly Foam Shop in the University District and used 1/2" foam, but there is a wide range of options available depending on how you want your headboard to look and feel. They cut the foam for us, but if you're cutting it yourself, place the foam over the plywood and cut to size. Use spray glue to adhere the foam to the plywood.
This step is optional, but the batting will help smooth the edges. Lay the batting on the floor, and place the plywood, foam-side down, in the middle of the batting. Cut the batting slightly larger than the foam core so that its edges wrap around the sides and onto the back of the board.
Use the staple gun to attach the batting to the plywood. Pull the batting taut as you move around the plywood, stapling every 2-3" around the edges.
Place the fabric face down on the floor. Go over the fabric with a hot iron to remove wrinkles. Place the plywood (just as you did with the batting) foam-side down in the middle of the fabric. Cut the fabric slightly larger than the foam and plywood so that its edges wrap around the sides and onto the back of the board. If you use our dimensions and the 2 1/2 yards of fabric, you won't need to make any cuts.
Rinse, later, repeat. Staple the fabric just as you did the batting. Pull the fabric taught around the edges and staple, roughly 2" apart, around the entire length and width of the plywood. The edges can be tricky, so take your time.
Mount your headboard. We ripped (which means to cut in the direction of the grain) a piece of 1x3 Douglas Fir at a 45 degree angle—affixing one half to the back of the headboard and the other half to the wall. We used a table saw with a multi-use blade and a ripping fence. If you don't have these tools (or expertise) available to you, the Bellevue store will rip the 1x3 for you. One free per customer! Just mention the Dunn DIY project and someone will gladly help you. We also screwed a 1x2 piece of Douglas Fir into the bottom of the headboard so that the head board hangs vertically and not at an angle.
Another option is to hang the headboard like a picture. Attach picture wire to the board and drive a couple of large picture hanging hooks into the studs. Make sure that you use enough for the weight of the headboard. The big ones can hold about 50 lbs each.
Admire your handiwork!