how do I play againts other people in halo 3?

[Dot...]

Yeah have live. No friends are online so how do I play against randoms?

 

[Kyle P]

Go Into "Matchmaking" from the main menu then you'll see a list of options, just select your playlist (if your new i suggest going into one of the Social Playlists, which means they arent ranked) and select "Start matchmaking" and you should be good to go