Is this the stocking you are talking about?
Christmas Stocking by Nicky Epstein
What part of the pattern are you having trouble with? Is it row 1 of the "Divide for Heel" section or row 1 of the first "Turn Heel section"?
Part of doing socks, when you are turning the heel, is that there will be stitches left on your needle at times, and you will turn the your work and leave those stitches alone. In other words, they will be left un-knit for a little while, you just ignore them. They won't be forgotten forever though, you'll come back to them later.
(I'm not super familiar with gusset socks, I prefer short row socks. So I may be wrong about exactly what to do with the style of stocking you are trying to make.)