Hmmm...I sympathize with the original poster's plight. I'm no idiot, but what I thought we were getting was a game plugin, much like A-10 or BS, that would come up as an option when you started DCS World. From the docs, it was not obvious to me that this drops in more like an add-on to existing games. I, too, was looking for a "combined arms" button off of the launch menu. My expectation certainly was highly involved in my not understanding the manual and what the game is and how you access it.
My suggestion: Put at the very top of the manual: "How you start Combined Arms", and then include, in gory detail, that the game is not a separate game launched from the DCS World menu, but rather it is accessed from within other game modules when you are flying a mission. Yes, I see now that the info is in the manual, but it didn't click for me when I first read it because I just wasn't expecting it to work this way.
My 2 cents...worth all you paid for it...