Socks Knitting

This is my first time knitting socks. The pattern says the following:
Next row: (WS). P9. P2tog. P9. 19 sts
Next row:K1. Sl1
Repeat last 2 rows for 2 ins ending with RS row

what is WS, Sl, and RS
What does psso mean?

Is there a video to show knitting socks?


WS - wrong side
RS - right side
Sl - slip
PSSO - pass slipped stitch over

They can be found on the glossary tab linked at the top of the page.