Locate the Content/0000000000000000/545408A7/00000002/ folder within the extracted files.
Once the base game is installed, additional DLC (like the Beach Bum or Heists packs) follows the same logic. Grand Theft Auto V [Jtag/Rgh DLC]
Copy the four data files (typically named 545408A700000001 through ...04 ) into the corresponding path on your Xbox 360 HDD. Grand Theft Auto V [Jtag/Rgh DLC]