When I want to stitch the binding in place by machine, I fold it to the back a bit at a time and I put a straight pin from the front to catch it in place. The pins are vertical to the binding. right where you want to machine stitch. I do take care to pin two or three pins on the corners. The one I just made worked well. I got all four corners sewn down well. Sometimes I do miss one. good luck. (I remove my pins as I sew along)