Instructions
Insert your USB hard drive into an available USB port on the front of your Xbox 360.
Navigate to the "System Settings" menu option in the "My Xbox" section of the main dashboard and press "A" on your controller.
Scroll down and select "Memory" from the "Systems Setting" menu.
Select the hard drive from the "Storage Devices" menu.
Select the content you wish to transfer by highlighting it and pushing "A" on your controller.
Select "Move" from the list of available options.
Choose your USB hard drive device from the list of available transfer destinations. Press "A" on your controller to initiate the transfer.