Turn the chair upside down. Locate the screws below seat. Unscrew the bottom of the seat to expose the existing fabric and staples.
Pull the staples or fabric tacks out with pliers or a flat-head screw driver. Discard old staples or tacks into the trash.
Pull the old fabric off the seat. Discard the old fabric into the trash. Set aside the seat.
Unfold the new fabric. Lay the seat bottom down on top of fabric to measure as a template. Cut enough fabric to wrap around bottom of seat. Add 4 inches to all sides.
Measure the fabric and mark with the pencil on backside of the fabric. Cut carefully along your line you measured.
Place the fabric right side down on a flat surface. Place the seat cushion bottom up on top of the fabric. The right side of the fabric should be facing out before you begin stapling.
Pull the fabric tight and start stapling the fabric on one side. The extra fabric will be cut down later. Start with one side, then move to the next. All wrinkles or folds should not visible from the top of the cushion.
Trim off the excess fabric and uneven edges with scissors, leaving about ½ inch all the way around.
Turn the chair in upright position. Place the covered seat cushion back on the chair. Screw in the hardware tightly back into the existing holes, using a screwdriver.