I found this old folding chair in my parents' garage and decided to give reupholstering a try.
Luckily, the little back part popped right out and the cushion unscrewed.
I traced around the cushion with newspaper and added a couple inches seam allowances.
I got a staple gun and stapled the fabric around the new cushion.
Then I sanded and painted the chair frame brown instead of the black.