1, you better go check the tutorials if you want to go into detale but the basics is that you create your own army in a launcher and then send them to fight eather the axis or the allies(depens on what side you are on).
http://forums.europeinruins.com/index.php?board=44.02, it is quite good but it is mostly in later part of the days that they are here.
3, you will have to make up your own mind on how you thing about this mod, currently there is a war between the makers and balence members of the mod and the players but it should not really be a problome for you unless some idiot makes it.