Halo 3 change appearance!?

[High 'N' Dry]

I just got Halo 3 and I am confused. Where do you change the way your character looks for multiplayer? Like where to you pick your color and symbols and whether you wanna be a spartan or an elite? I seriously cannot find how to do this! Someone help!
And another thing, when I play multiplayer with just two people, the screens are smaller than normal. How do I fix this? Or is it supposed to be like that?
Ok just found out how to change appearances lol.

About the screen...yeah, I know it has to split screen. But it's still smaller than the Halo and Halo 2 screens. On both sides of the screen there are two vertical black bars, making the screen much smaller. Can I change this?

 

[??IH8DUMPPL??]

I'm not certain on the changing appearance but for the screen size your getting during two player multiplayer I believe that is normal for any console game when you're playing multiplayer. It has to split-screen. I have an invention they should make... on a Gaming Console, in the back will be 4 special video ports, the first one ofcourse is the main and default port for Single player, etc. If you are doing multiplayer you can actually use the 1st port for first player on a tv and then connect the 2nd port for the second player and so on to another tv so you don't share off the same t.v. and get those annoying Split-screens. I believe they can probably some how invent that. It would be pretty cool. Hope you get your problem solved, take it easy.