Cut a piece of 1/4 inch plywood to 2 inches smaller all around than the size of the completed headboard.
Divide the height of the plywood sheet in three, then draw three level lines across the width of the plywood. Divide the width by five, and draw five true-vertical lines across the length of the plywood. The cross points are where the button holes will go. Alter the number of button holes by dividing the height and width by a smaller or larger number.
Drill a hole, sized to fit the upholstery needle, right through the cross points of the lines.
Cut a piece of hypoallergenic foam to the size of the plywood sheet with an electric knife. Spray glue (following the glue label's instructions) on the plywood, then attach the foam to it, ensuring all the edges match up. Cut a piece of foam batting to the same size, and attach it to the hypoallergenic foam in the same manner.
Cut a piece of upholstery fabric 5 inches larger on all sides than the size of the plywood, foam and foam batting. Spread it out face-down on a work surface.
Place the plywood on top of the fabric with the batting-side down. Pull the middle of each side of the fabric up and over the back of the plywood and staple it down. Turn the plywood over to check that the fabric is sitting straight, then continue pulling the fabric over the back, alternating sides with each staple to achieve an even pull. Trim off excess fabric with scissors.
Hammer a staple halfway down next to each of the drilled holes at the back of the plywood. Thread the upholstery needle with upholstery thread, and tie off one end onto the staple next to the hole.
Push the needle straight through the hole, up through the foam, batting and fabric, and pull it until you see the thread taut on the staple. Thread a covered button onto the needle, then push the needle back through and out the hole again.
Pull on the thread so that the button is pulled back into the fabric, making a depression in the front. Keep the thread taut, and tie it off on the staple. Cut the thread, then hammer the staple the rest of the way into the plywood. Repeat on all the holes.
Cut two lengths of 2-by-3 lumber to the height of the headboard, and two to the width. Trim the ends of the pieces to 45 degrees, so that when the pieces are put together to form a frame, the ends mate forming 90-degree corners.
Drive two 3-inch nails through each corner to secure the frame pieces. Paint or varnish the frame as desired and leave to dry.
Fit the frame around the tufted headboard center; it should fit snugly. Adjust the frame so that it sits flush with the front of the headboard, with overhang at the back. Secure the frame to the plywood of the headboard using finishing nails and a hammer.
Mark a level line on the wall at the desired hanging height of the headboard. Locate the wall studs with a stud finder, and mark them on the line as well.
Cut a length of 2-by-3 lumber for a cleat, or support, that is about 1 inch shorter than the width of the headboard frame. Place the cleat on the plywood to check if it will protrude past the level of the frame at the back -- if it does, trim the thickness on a saw so it sits level with the frame at the back.
Place the cleat on the wall line and secure it to the wall studs with 4-inch drywall screws; 2 per stud point. Place the headboard over the cleat, hanging it by setting the top of the frame on the cleat.
Push the headboard back against the wall so it is flush, then secure it to the cleat with 3-inch nails hammered through the top frame of the headboard into the cleat.