Capturing halo 3 multilayer clips?

[someone]

I know u go to theater mode but do u have to host my own game or how do i record in matchmaking. When im in theater mode im all alone what do i do thanks.

 

[Dowell]

when you are in theater go and hit the "x" button and a thing should pop up with different icons on it click the one that is like a dot

and no it can be within the last 25 games you played so no you dont need to host it

 

[You killed alan]

All you do is go into theater, and when the film is playing, press X, and a blue button bar will come up, and just click the Record button on the bar, and it will begin recording, then click it again to stop recording.