First start by stapling down the four centers of the cushion , making sure fabric is kept semi tight. Next staple down midway between these staples and the corner of the cushion.
Staple down triangle edge
Adjust your excess fabric by tucking and creating equal seams on both sides of the corner
Repeat for all corners
Measure fabric for area, leaving about 1" excess on all sides. Again, tack all four centers first, keeping fabric tight.
Next, tack fabric on either sides of the existing staples, leaving corners untacked.
Fold and tuck corner fabric, leaving no excess outside of the edge of chair ridge. Staple into place. Remember that is not necessary to over tack fabric because you will be tacking on another layer of fabric and adding nailhead trim, which will provide adequate securing of fabric
Repeat previous steps, just folding excess fabric internal towards the padding so no excess is exposed. Secure all four centers first.
Repeat corner folding and tacking as previously done.
Nail first nailhead down and continue nailing until you reach one nail head hole before the corner. Be sure fabric is not sticking up between edge of chair and nailhead trim. Any imperfections or gapping in fabric will be hidden by nailhead trim.
Once you reach the corner, cut nailhead trim from roll at the last faux nailhead that is closest to corner. You will not always land on a nailhead that requires a nail, therefore it is important for your next corner piece to start with a nailhead that requires a nail. Cut any excess faux nailhead off and continue down the next side of chair.