Sewing a buttonhole with the buttonhole foot

The buttonhole is usually sewn right at the end of the project when everything else is done. What if it messes up, gets all tangled, is skewed or just plain untidy? It must be very hard to unpick a tiny buttonhole and resew without damaging the fabric. And what if there are several, say 6 buttonholes to sew. That means 6 chances to make a mess. To do it nicely, each and every one has to be sewn correctly. Getting it right on the first try, every time. I’m perspiring just thinking about it.
Nothing to be afraid of at all. Now I am almost confident that if I had to sew a buttonhole, I would get it right first time and not mess up all my hours of work. Here's how to do it.