Instructions
Place the Halo disk into your Xbox, and wait for the content to load. Scroll to the "Play Halo" option using the left stick, then press the "A" button on your controller.
Scroll to the "Start" menu when the game loads. Press the "A" button.
Highlight the "Media" option using the D-pad or left stick, then press the "A" button. At the "Media" tab, scroll to "Settings" and press the "A" button. Then scroll to "Appearance" and press the "A" button.
Scroll to the "Race" option. Scroll to "Human," then press "A" to select the smallest possible character.
Return to the "Appearance" menu, and scroll to "Armor." Look through the available armor options by moving the D-pad or left stick. Locate the smallest possible armor, and press the "A" button.
Change the color of the armor if desired. Scroll to "Color" within the "Armor" menu, and move the left stick to the right. Highlight the appropriate color, then press "A." Changing the color of armor will not change your character's size but it may make him easier to harder to see, depending on the color you select.