Coop Multiplayer

[Janz]

Hi ,
Can anyone who knows please tell me how to ensure/make a map work in cooperative mode.
So far i have tried many maps in GEM to see if i can pick that specific up but no luck.
Just the basic [e.g. 0.mi and it must have a tag "autoassign" and then tag each soldier's mid to allow it??...but that was my best guess and did not seem to work.]

Thanks in advance, and i do hope one of you has the knowledge and time to assist - it will be greatly appreciated.

Janz