How to use a flat-felling foot

After I flipped through David Coffin's Shirtmaking book, I ordered myself a flat-felling foot from my local sewing store. It came in, I went to pick it up, and I asked the relevant question - How do you use it?

We couldn't figure it out, and so the guy turned to an old Singer reference book - dated 1946. (I didn't take a picture of the cover, sorry!)

So, here's how, in Singer's words:






Enjoy! As for me, now that I know, I'll be practising.