If you want to play with a friend, you can play go on MULTIPLAYER and pick the option. It should work if you are on lan. If you are not, you can use programs like Hamachi to create a virtual lan, so you can join your friend's game - or the other way around. For people who don't understand alot about how this things work, it can be a pain in the ass to play using the MULTIPLAYER option...

 

But i have good news for you: DO NOT use it then. Why is that? Well, you can play on a Matchmaker for free, with easy installation and setup, with 2, 3 or 4 players in a game. There is an active community where everyone knows everyone, which makes it a funny, warm but disputive community. You can play with the players you want, ranked games or unranked games (for fun, without being afraid of losing points), and the best of all is you can play tons of new levels! It is so much better to play on a matchmaker that it's safe to say The MULTIPLAYER option should not be used again.

 

You can read the other parts of The Populous Bible talking about online services to learn more about this matter. Don't wait any longer, online games are waiting for you!