What's C2 over 2 right and c2 over 2 left mean?

Lovely scarf but they are naughty not to put a key in. C stands for cable, and normally it would be F or B for forward or back. If you are wanting to go towards the left, you will put 2 (I guess) on the cable needle, put it to the back, Knit 2 and then then knit the two on the cable needle. And Forward for the right lean.