Help! How do I save my progress in halo 3 in campaign mode??

[Product of Conception]

Pls help! Every time me and my wife play in campaign mode using 2 controllers it doesn't seem to save our progress It only seems to save when I play by myself in a solo game. This last time we got hooked and stayed up playing and got really far so I ended up just pausing the game and not turning it off till I figure out whats best. Can someone either tell me how it's done or that it's simply not gonna save it so that I can turn off my xbox before it fries? Thanx!

 

[randomguy1989]

not sure, dont got the game sorry. try searching on how to save it on google or w/e.