I am attempting to make my 1st pair of socks, now I'm confused about the "making the heel" part. According to the pattern it says to "work back and forth" until heel measures desired length. Then it has the "shape the heel" part that says after each completed row to "turn" before starting the next row. What is "working back and forth" and "turning"? Is there any good videos (free to view on the internet) that could show me how to do this?