there are instructions in the pause menu...
No, halo 3 forge is not offline, you may play it online with friends or others.
No! Forge World on Halo: Reach is completely free, provided you have the game and Xbox to play it on!
You can't
no you cant
On halo 3 you can't so I would doubt it
No, you don't.
Play locally.
Yes, Halo: Reach will include Forge.
Yes, there will be forge mode in Halo 4.
You go on custom games(not forge) and select a map and you're on without forge
Yes, it will have forge
you can on forge and custom games.