Things You'll Need
Instructions
Attach your hard drive to the Xbox 360 and turn on the console. Wait for the Dashboard to load fully then sign in to your user profile by pressing the center "Xbox Guide" button on the controller and then the "X" button. Select your profile and press "A" to sign in to your gamer profile.
Eject the disc tray on the Xbox 360 and insert a game disc. Close the tray and wait for the Dashboard to read the game. Press the "Y" button on the controller to begin installing the game to your Xbox 360 hard drive.
Select "Install Game to Hard Drive" with the analog stick and press the "A" button on the controller to begin copying the game ISO from the Xbox 360 game disc to your Xbox 360 hard drive. Wait for the install process to complete then restart your console. You can play the game from your Xbox 360 hard drive at any time, so long as the original disc is inserted in the disc tray.