STRAIGHT THUGGIN

You need Six Updater to get the mods required for CO.

http://www.six-updater.net/p/download.html
Download the latest dev version

Installer will ask if you want to enable multiplayer features.
Yes, you do.

Once in the program, check the server browser and find "KC /int/"
right-click KC /int/ and select "New preset with server"

"Server KC /int/" will appear as a preset in the list to the left
right-click that preset and chose "updater actions install or update mods"

Mods will have green icon in the list when installed and up to date

If the KC /int/ server is not online you need to manually create the preset
Current preset for KC /int/ is:

@ACE
@ACEX
@ACEX_RU
@ACEX_USNavy
@CBA
@fallujah
@CLAfghan
@mb_objects
@opx_objects

NON-SIX DOWNLOADS REQUIRED:
http://www.moddb.com/mods/yoba-ace-mod-pack-v10/addons/yoba-island-pack-v10
- includes all custom islands we use except for fallujah and clafghan. The mod itself isn't explicitly required, but all the islands in it are, so if you don't have them then you should download this rather than all of them separately.

HOW TO RUN CO WITH THESE MODS:
Put "-mod=@cba;@fallujah;@clafghan;@yobaislandpack;@mb_objects;@opx_objects;@ace;@acex;@acex_ru;@acex_usnavy" in launch options for steam or in shortcut for non-steam