When picking up sts on the back neck, or anywhere you're working with a finished edge, the easiest way is to pull a loop of yarn up with a crochet hook (as many times as stated) and place it on your right ndl. You can also go down thru the sts with the tip of your ndl and pick up the yarn loops but a hook makes it easier. (There's a vid on picking up sts in the Vid tab above.)
YO is in the Glossary...tab at top of page. The YO, combined with the K2tog, forms an eyelet bh.
Keeping to the knitting basics