The YO counts as a stitch only after you make it, it doesn't use a stitch, it adds one and you just wrap the yarn around the needle like you do for a knit st. The ssk is a dec (which offsets the yo inc). Slip 2 sts knit wise from L to R needle, insert the L needle into the front of them and wrap the yarn around the R needle to knit them together. There's a video on the Decreases page and the YO is on the Increases page. Or you can find them and a lot of other terms with videos on the Glossary page.
sue- knitting heretic