It's impossible... Unless you mod the game but that's illegal so don't mod
You can't
Sorry, I think you can't do this unless you mod halo 3.
There is no Halo 3 mod for Halo Trial. Halo Trial is one of the hardest versions of Halo to mod. There are however, custom maps for Halo Custom Edition. To get Halo Custom Edition, you need to have Halo: Combat Evolved installed on your PC, you also need your CD key. You can download Halo: Custom Edition free.
You can't install Halo 3 mods anymore to your xbox.
there is no such thing
You cannot. This is impossible.
its easy download it at filefront.com copy this where halo trial halo 1 halo 2 halo 3 mod mods ok?
yes, yes you can
No
Yes, you can mod campaign mod on the Halo trial.
No there is not a mod