Lay the seat piece and cut out your fabric. Leave a generous margin 2-3 inches around on the outer fabric. You do not need a margin for the fleece. I did my fleece three layers thick and it’s super comfy. Place the fleece in the middle of the top fabric.
Lay the seat piece on top of the fleece and start taping by pulling the side over and taping to keep the fabric in place. It should be taut but does not need to be super tight since when you put it on the frame that will need some room and hold the fabric in place. Pop seat top on (I had to use my knee for some extra umph). Don’t worry it pops off really easily so if you want to make a pouch you still can.
Lay seat back on top of fabric and trace with a fabric marker. I layed it, traced around the side and rounded edge then rolled it over to get the top edge and layed it down and continued tracing. Cut around leaving a 1 inch margin on each side and along the top and a 3 inch margin along the bottom. Cut. Lay over the back rest to check size.
Fold bottom edges over making sure not to fold too short. You do not want any of the back rest to peek out. Hem both bottom edges. Fold in half with right sides together and stitch up both sides. You should now have a little pouch.
Rightside out the back rest cover and slide over the back rest. Tuck in the top corners of back rest cover and you’re good to go!