Welcome to the forums
To find games this forum is probably as good a place as any.
To connect to each other it depends on whether you're on the same LAN (generally speaking, behind the same router) or not.
If you're in different places: have one person start a game (get into the lobby I mean, though joining midway is also possible) and have the other use the direct-connect option and enter the other person's public IP address (
https://www.google.com/search?q=what%20is%20my%20ip is one way to get yours). Or you can use a VPN like hamachi to simulate a LAN.
If you're on the same LAN then the multiplayer function should find the other person automatically if they're in the lobby or allowing a midgame join (using "Manage Players" from the escape menu in-game).
