'the installer is probably about a gig but the files you have to download are like 3 gig'
You download the installer which is 1.4GB.
That's the only thing you need to download.
Then you said. "but the files you have to download are like 3 gig".
you download the installer which is like a gig, then the installer downloads the files that are necessary to run combat arms and installs the files you need to play
am i not writing my messages clear enough?
The installer packed itself all the files needed and compresses it.
After you run the installer, all it does is unpack itself and goes to the installation folder, Combat Arms.