reading sheet music

This is a 3.93 minute video response from Matt Brown on Nov 1st, 2008

Question:

"Scando says "Hi there, I am working through a classical guitar book and have come across some annotation I don't quite understand. C.2 --- C.9 --- C.2 --- C.1 --- C.7. What do the various C's stand for? Hope my diagram makes some sense Lars""