How do i use the Assassin's Creed 2 GotY Edition DLC on the Xbox 360?

Question

I got Assassin's Creed 2 Game of the Year Edition for the 360 and the slip inside says it comes with DLC which was the reason why i brought it. when i got Borderlands Game of the Year Edition for the PS3 there was an extra option in the PS3's main menu which took me to the installers for the DLC.

The PS3's menu layout hasn't changed very much however the 360's have changed quite a lot, evey time i have never found a separate option to install the DLC.

I am wondering, how do i install the DLC for the game of the year edition for the 360 using the latest version of the 360's menu?

EDIT: i completed Sequence 11 and learned of the repaired 12 and 13 which i assume to be the DLC, yet there was no prompt at any time that it had been installed, while i could assume it was installed at first start up along with the achievement list since this was the first time playing it on my 360 this would mean that the DLC wont install on my dad's 360 because he's played the original and when he puts the game in and starts it up it doesn't install a second Achievement List or indicate the game needs to be updated but this would make no sense then.

So i'll change what i'm asking here, how/when did the DLC get installed without prompting me

Answer 1

In A C 2 GOTY you must progress through the story mode to start unlocking the DLC. No code required like on other GOTY and non GOTY games. After about sequence 12 - 13 you will begin to unlock some of the DLC features, as you've already experienced. The DLC was downloaded as you began to progress far enough in the game and get enough codecs. Beat all codecs and story mode to unlock and access all DLC content without any codes.

My proof other than experience: http://forums.ubi.com/showthread.php/472525-assassins-creed-2-game-of-the-year-edition-help-Forums