Once you have the DLC downloaded you’ll need to copy it over to your 360.
The simplest way to do this is to FTP the files across or by using a USB Flash drive.
Depending on where you obtained the DLC content for your game it may be zipped, and could have a variety of folder structures. eg /00000002/2F5DF3FFC9BF2582C3B48D7395ADD0D20359BD1D54
or just one long file eg. 2F5DF3FFC9BF2582C3B48D7395ADD0D20359BD1D54
The file containing the DLC is the long one with all the letters and numbers! What you need to do is copy that file to the 00000002 folder within your game directory on the 360.
You will need to find or already know the title ID of the game that you wish to add the DLC content for, gamesdatabase.org is a good source for this.
Once you have the title ID you will need to locate that directory on your 360’s game directory (Use aurora to check the HDD games path if you’re not sure which drive or path your games are located) Now, once inside that games folder you will need to create a new folder called 00000002 if it doesn’t exist already. Finally, inside the 00000002 folder is where you copy any DLC files for that particular title.
example location for Red Dead Redemption DLC
Now, like title updates just make sure that they are activated and listed within the Aurora dash, once they are you’re good to play!