There is few ways to invite other players - thies will automaticly make party if invite is accepted

1. Plus [+] button under your pilot icon - this one is for adding friends that are curently online
















2. Player cards from friend list or global chat - click on name of player you want to invite from global chat or your friend list then once player card opens click plus [+] button to invite them

















3. Inviting player from world map - click on their mech in world map and click invite

Once you are in party with someone you invited go to map lobby and start it like you normaly do (running to right side and clicking space or doublclicking right side)

Not all maps can be played coop - all maps before basecamp are solo only and mech maps are also solo only