choose your level, then click X, find the skull(s) you want and click then, then press b and start your mission
To select the skull menu in Halo 3, go to the main menu and choose "Campaign." After selecting your desired mission, press the "Start" button to access the pause menu. From there, navigate to "Skulls" to view and toggle any available skulls for that mission. This allows you to customize gameplay with various modifiers.
No
The first skull on halo 3 is a silver skull. Silver skulls do not award any achievements.
If you don't start the level from the beginning the skull won't appear. If you did start from the beginning i don't know.
After finding a halo 3 skull, simply pick it up as you would any other weapon.
You can play Mythic on halo 3 by activating the skull before you start the game.
once you get a skull in halo 3 you can co to the campain options and turn it on different skulls do different things
13
http://www.halo3planet.com/halo-3-skull-locations/ is were I found them
You do not jump through rings to get the tilt skull in halo 3.
The last skull is the easiest one to get, start the last level and go as normal, but as you go into the cave look at the right wall and there should be a smaller tunnel you can follow, the skull is at the end of the tunnel.
the fog skull takes away your radar. you find the skull on floodgate