Don’t really need the link for that one, it’s basic socks 101.
You know how you knit back and forth to do the heel flap? That is what turning is. You just turn it over and knit the other direction, yes even though there are still stitches left.
Trust the pattern.
It took me about 3 pairs before I understood what was going on and I still have to look at a heel turn pattern to get started.
That is a short row. It’s making a succession of shorter and shorter or longer and longer rows to make a hump in the row of knitting.