AI:
create a new game (host)
add a team by left-clicking an empty team slot
afterwards rightclick the field right to the color field of that new team (called extra field) in the lobby so that it says "AI"
also change the color of the new team so it becomes your enemy.
you can repeat that to have more AI teams. you can even let AI fight against AI but that's boring
note that the current AI is only random and no real opponent. consider to download another AI script from the file archive.