Use a flat headed screwdriver to remove the screws holding the seat attached to the wood frame. Be sure to keep the screws, you have removed, at a handy place because you will need them later. Furniture padding will be revealed once the seat has been unscrewed.
Remove any staples or tacks embedded in the padding with the flat headed screwdriver. Once all the staples or tacks have been removed, start removing the old fabric. Keep in mind that the material you remove would have to be used as pattern for the new covering. For this reason, give it your best effort to remove the old material in one piece.
The foam padding in the furniture item you are reupholstering, needs to be replaced. If the foam is glued to the base, you will first need to pry the foam off and then remove the glue residue as well.
Cut a thick piece of foam thick enough to provide the desired amount of softness. The dimensions of the piece of foam should be at least half an inch larger than required. Apply a thin layer of adhesive glue onto the board and affix the foam in place.
To cover the foam, cut a piece of fabric having the same size as the one you had removed in the second step. However, you would need to compensate for increased foam size.
Install a staple using a staple gun through the covering fabric and into the wood, at the back of the board. Stretch the fabric, remove any wrinkles and install another staple at the front of the wooden board. Continue in a similar fashion until the new fabric is properly secured in place.
Pull the new fabric over the corners and staple it in place. Be sure to keep the bend as neat as is possible. Cut away excess material with sharp scissors when you have stapled all the corners.
Finally, screw the seat back in place to finish the task.