In the videos, above, go to decreases and in that, go to SKP aka sl1, k1, psso. See how she slips one stitch over the other at the very end? That's what you're going to do, one at a time, over and over, until you've used up all the sts. So with all the sts on the right hand needle, start at the left, and with the empty needle, lift the 2nd to last st over the last st. Now take the next st and lift it over that last st. Keep doing this one by one, until you've used them all up. You are working left to right through your sts. I haven't ever seen doing that many sts (21!), but I guess it works.