Complete noob to halo 4.
I used to love firefight on halo reach. The one where you kill aliens in waves along with random people on internet against the computer generated aliens.
How do I do this on halo 4 as I can’t find any kind of games where I’m playing with random users instead of against.
Spartan Ops. Its somewhere on there.
Sorry to say that you’re out of luck when it comes to finding straight-up Firefight in Halo 4. Spartan Ops, though, makes for a pretty good substitute! 
> How do I do this on halo 4 as I can’t find any kind of games where I’m playing with random users instead of against.
Spartan Ops Matchmaking. When you first boot up Halo 4, select these menu options:
War Games -> Spartan Ops -> Find Game -> [pick a level]
Doing that will start a search for players. You may see some familiar elements from Matchmaking – indicators of players that have been found, and population counts next to each available level, for example. Note that while you cannot play all levels at a given time, Halo 4 will generally present you with each level from a given Episode, changing Episodes on a weekly(?) basis.
Thank you everyone. After reading these I found Spartan Ops and really enjoyed it. Like how you kill aliens together but its a tiny bit like a story. Thanks again guys!
I prefer Spartan Ops to Firefight actually, I really like the tidbits of story accompanying each mission.