Stuck on a pattern...please help?

Hi, this is my first time knitting a sock, I am stuck on a few things: in the first paragraph I don’t get the underlined part - about doing the yarn over? How does this differ from a regular P2tog tbl?

Row 2: Sl 1 purlwise, Purl to last 3 stitches, P2tog through the back loops (tbl), P1, turn. (If you have never purled two together through the back loops, what you need to do is turn to the back of the stitches on the left needle, insert your right needle into the back loop of the second and first stitches on the needle, in that order, [U]then turn the work to the front again and yarn over, completing the purl as you would normally[/U]

Secondly I’m confused on the below paragraph - what does she mean by ‘pick up stitches’? I don’t understand this piece at all…

Row 5: Sl 1, K to end, then with same needle pick up 6 stitches along side of heel, using slipped stitches as a guide. You will be inserting your needle into the back edge of the slipped stitch, yarning over, and pulling that yarn-over through the slipped stitch to create a new stitch on your needle.

Please help if you can! Thanks

This is an explanation of the p2tog tbl. It’s the same as the usual p2tog tbl. The yarn over is just meant as part of the purl stitch.
Under the Free Videos tab at the top of the page, Advanced Techs, is a video for turning the heel of a sock. It may not be the same as your directions but about halfway through, there are directions for picking up sts along the side of the heel.

Super helpful, thanks!!