Remove the cushion from the chair with a screwdriver and set the cushion aside.
Sand down the chair with a power sander connected to a shop vac. Use 160 grit sandpaper to smooth the surface.
Wipe down the chair with a soft sponge and warm, soapy water to remove any traces of dust and fiber on the wood. Rinse and dry.
Leave the chair overnight to allow the water to dry completely. Sand the dry chair with 220 grit paper to smooth down the surface and remove inconsistencies in the texture.
Prime the chair with a paint primer to prepare it for finishing. Leave the primer to dry overnight.
Apply the paint or stain to the chair in several coats until the desired color is achieved. Let each coat dry thoroughly before applying the next one.
Pry off the staples on the underside of the cushion with the end of the screwdriver. This will allow you to remove the fabric upholstery on the cushion.
Trace the shape of the upholstery onto the new fabric using a pencil. Cut out the traced shape with scissors.
Lay the new fabric on top of the cushion with the right side of the fabric facing up. Turn the fabric and the cushion over so the underside of the cushion is up and the upholstery is face down underneath it.
Pull up one edge of the fabric around the cushion and secure it in place with a staple gun. Work around the fabric keeping the fabric held firmly until the cover is stapled completely in place.
Put the covered cushion back onto the chair and screw in place from the underside.