Halo 3 question plant the bomb?

[Captain Clutch]

hey there, i'm knew to halo 3 and my friend invited me for a game and i accepted. it was plant the bomb but i had no idea how to do so or what i had to do. how exactly do u "plant the bomb and score points"? are u supposed to pick up some bomb and plant it somewhere and where is the bomb? how do i plant it? what buttons do i press?

thanks!

 

[Phillip]

I think you pick up the bomb and then put it in the spot where it tells you to.