Xbox 360 Halo 3 Help?

[cassieSWAGS.]

For Halo 3 on Xbox 360...if I want to join an online party, or start one, how do I do it? But, the only thing is that I DO NOT have any friends, at all. So how can I join one with random people? What do I do? Please nothing rude!
Help is SO greatly appreciated, really(= Thanks!

 

[Walkmo]

for joining random people its matchmaking but you cant control the game and you need xbox live gold