The first problem — a chewed-away zipper bottom — is quite common, but requires no sewing to fix. As you’ll see in the video below, all it takes is a drinking straw, some hot glue ...

If a missing or broken zipper teeth at the very top or bottom, you can sew a new zipper stop above the missing teeth to prevent the slider from moving past the gap. If the missing or broken teeth ...

Do this on both long edges. Using the zipper foot, sew along the piping. Place another 3 x 9 rectangle on top with righ sides together and pin. Turn the pieces over so you are sewing on the back ...