There is a saying.. when all else fails, read the help file
Sorry to be a smartass
You have to setup a match if you want to play someone other than the bots.
To setup the match click the top left icon on the toolbar./
Then the play icon will show for your opponent and they can join and you can accept
I know its different from FIBS but this is not fibs anymore
The FIBS system is not so good as it doesn't let anyone know what kind of match you want to play
This is similar to the play65 style lobby if u ever played there.