Co Op
Overthrow is designed for co-op play and anyone in small groups. Just you and a buddy is plenty but the real fun starts when there are 4-6 working together.
Starting a co-op game From the Arma 3 main menu click on "Multiplayer" and then "Server Browser". From the screen that shows you want to "Host Server".
- Give your server a name, any will do
- Change "LAN" to "Internet"
- Select "UPNP"
- Give your server a password if you like (or not if you don't care who joins you)
- Click "Host server"
From the next screen simply choose the "Overthrow" mission and click "Play".
Once in the game it is easiest to invite your friends via Steam. Press Shift-Tab, find your friend, click the small arrow next to them and "Invite To Game".