Remove existing upholstery and all staples and tacks from the seat frame. Discard the items.
Measure and record the chair seat dimensions, including the width from side to side and front to back, along with the seat depth.
Measure the batting or foam using the seat dimensions, leaving an extra ½ inch on each side. When you stretch the fabric over the seat pad, the batting or foam will shrink a bit.
Measure the fabric, leaving 2 to 3 inches on each side. Place the batting or foam in the seat frame and lay the fabric over the pad, centering the fabric evenly. Pin the fabric to the pad to keep it in place.
Flip the chair over so the bottom of the chair is facing you. Pull the back piece of fabric tight and fold the corners neatly where the back fabric meets the side fabric. Insert several staples through the fabric across the bottom of the seat frame with the staple gun. Repeat this on the sides, folding the fabric where the front piece meets the side pieces. Finally, staple the front fabric in place.