How do you customize your character is halo 3 online?

[eccmms]

I know I unlocked some armor but I don't know where to go in the game to change myself.

 

[Infam0us_Azn]

When you are in the game, press start.
Then move your left joystick to the right.
Click on appearance.
Now you can change your head,left shoulder, right shoulder, and/or body armor.

 

[Kris M]

press start go right on the d-pad and go down once the game starts you out with two tieps of armer but you can get more by getting achevments