go to custom games and look at the maps, it should show a star next to any new map u downloaded
go to custom games lobby then to select map then go to the right map :)
go to bungie and download the map WHILE YOU ARE SIGNED IN TO BUNGIE.NET and you will get a message after the download on the computer that it will be downloaded when you are connected to xbox live and in halo reach.
The makers of Halo 3, Bungie.
Besides the maps that come with the games, no.
I wouldn't if i were you, bungie are cracking down on modded maps, my friend got his live acount deleted by bungie.
When you have downloaded them. They will automatically work.
go on machmaking
You look at "recent maps" and hope its there.
The mythic maps are officially coming out on April 9th, read the bungie posts on bungie.net.
well that is happening so try download it again
well I am not sure what you are asking but I will answer both ways. option 1:No you can not play all ORIGINAL halo maps, but you can download them from file share. option 2: yes you can play all maps from the start of the game!
on bungie, when you find the map you want, que it for download and when you next log onto halo 3 xbox live on your 360 it will automatically download.