This is related to No. 4 in this post . It was very difficult for me to work out how to sew it on the train. And finally I made the mistake by sewing the wrong way and when I turned out the right side it couldn't make right. So I had to rip the last seam. I finished it off on the sewing machine after folding and ironing. Now it's ready for snaps before it can be worn.
It's reversible, which I haven't done for a long time.