Verzosa

Hi all i'm new to ARMA to and it's really fun to play this game. But i can't join other server where there are many players on. First of all most players play on Moded servers. What is mod "CA"? for example? where can i download this mod. I manage to download some mods but i can't find this one "CA". I have at the moment: @ace;@acex;@acex_sm;@cba; which i placed in the root of Arma 2 (steam). Is there anyone who can help m3? Thanks