here are my DIY directions (i didn't have the patience to take photos step-by-step).
you need a plain plastic headband (the 1" thick size, NO TEETH), 1/4 yard of silk, glue gun, sharp scissors.
take your piece of silk and cut to 6" wide strip that is just about the length that it will take to go over the top of the headband, a little shorter is ok because you are going to wrap the ends. fold the edges into the center lengthwise, good/shiny side on the outside, and iron the creases in so it looks like a 3" wide scarf.
cut a thin strip of silk that will cover the inside edge of the headband (against your hair)--stretch taut and glue gun into place.
lay your "scarf" across the top of the headband and place it where it's going, then tack it down with hot glue in a few places so it stays in place. don't use too-big globs of glue or it will soak through and you will be able to see it.
pleat the ends of the scarf, one side over the other and glue the ends onto the headband one on top of the other. make sure there is at least a bit of plastic headband peeking out at the very end.
cut squares of the extra silk, about 3"x3"--these are going to be the end pieces. fold the edge in along one side (just a tiny bit, maybe 1/8 inch)--i ironed it in just to make it easier. tack this down to the inside edge of the headband and pull it around the top (don't squinch the scarf too much or the pleats will look weird). fold the bottom part up and glue into place (like wrapping a present) and the long edge over that. again, fold the edge under to make a clean line and glue into place. once you do the other side, you are all finished. the last step is the trickiest and takes a little practice to not get the glue everywhere--just go slow.