I found this You Tube video to be a very clear tutorial on how to do this. I didn't follow it exactly, but it's more or less the same technique. I've also found it easier to use a zipper that's too long and shorten it on each end. Trying to line up the metal pieces at the end of each zipper when you sew it in is just too fiddly an operation for me.
I also completed part 6 of Ele's ABC SAL. Why does that peacock look like a dinosaur to me? We just got part 7 and I I think may be going rogue on that one. We'll see.