How to play the pre-built Mass Effect world on Minecraft (xbox360 edition)?

I bought the Mash-Up, I know where to look for it, I have the rest of the mash-up (i think… I don't know where to find the music) i have re downloaded it several times (including from the home menu AND from the in game DLC menu, WHAT DO I DO!

After you buy it and it downloads it's already a map like where you would go to play on another map you have already built.