If I can't see the screen, what buttons should I press to update Halo 3?

[Stephen]

I don't have a T.V. next to my internet, so I'm wondering what buttons I need to press to update. I bought the Legendary Map Pack at a friend's house, and now I can't use it... Any help?

 

[xtrememan25]

you cant use it because it was at ur friends house and is on his 360 u is gonna hafta download it again but i dunno what buttons to press