It's A Plain But Very Elegant Scarf For Man

I intend to knit a scarf for boyfriend.  And yesterday I also found a pattern for a beautiful scarf on the internet

 

 It's a pity that knitting pattern is only chart pattern.

 I am having some difficulty with this scarf pattern. what's C2 over 2 right and c2 over 2 left mean? Look forward to receiving your instruction !!!