An old swivel chair
Enough fabric to cover the back-rest and seat of your swivel chair
Step 1: Dis-Assemble your Swivel Chair
Both the back-rest and the seat of the swivel chair are probably screwed into the main frame, have a look at your swivel chair and dismantle it. On the one pictured there were two screws holding the backrest in place and four screws holding the seat in place.
Once you have unscrewed the back-rest and seat, you need to take the padded part out of the frame, with this chair it was simplya case of levering the padded part out with a flat-head screwdriver (used as the lever).
Step 2: Cut your chosen fabric to size
Using the padded back-rest and seat as a guide, cut out your new baric, making sure you allow enough fabric to pull over the sides and staple into the back of each padded piece. I'd allow at least four or five inches all round.
Step 3: Staple your Fabric in Place
Using a staple gun, staple your new fabric to the underside of the padded pieces, starting in the middle of the four sides and pulling the fabric smooth and tight before stapling in place. Once you've secured the four sides of fabric work your way all the way round, stapling the fabric close together and overlapping to keep it neat around the curves.
Step 4: Replaced the padded pieces into the frames
Once you have stapled the new fabric all around each pice, replace the padded back-rest and seat into the frames and then screw the frames back to the chair base.