I wrote very extensive guides for HTTR and COTA. The game series sequence was:
RDOA -> HTTR -> COTA -> BFTB -> CO2
Now, the UI has been updated with each release. But for the most part, each UI update is a superset of the prior release. Also, my tutorials and tips spend a lot of time dealing with games concepts and how to play. Thus, applicability to CO2 is probably 80%. I say 80%, since there were three key additions that do impact general game play:
* Mixed mode movement. The road network became a lot more important.
* Supply simulation. Keeping your supply line open is important; the magic 3am Santa in your ammo clip doesn't happen anymore.
* Fatigue. Modeling of this kept improving.
Beyond that I hope you will find these tutorial of some use. Despite the variation in UI, it's like the difference between Mexican and Puerto Rican Spanish ... you'll still be able to make your way around.
You will find tutorial concepts, AAR, and tips how to play:
http://www.matrixgames.com/forums/tm.asp?m=554123
http://www.matrixgames.com/forums/tm.asp?m=554121
http://www.matrixgames.com/forums/tm.asp?m=977049
Good hunting!
PS: I think I was a member of the Beta Team for about 10 years or so. Almost long enough to learn some of Dave's Aussie English!