Instructions
Boot up your Xbox 360 and remove any disc in the tray to allow the console to automatically load the dashboard menu.
Go to the "My Xbox" section then press the right bumper button (RB) until you've scrolled to the "System Settings" menu. Open the menu.
Scroll to "Memory," then open it. Your console will ask you to choose a storage device.
Choose either the memory unit or USB flash drive from the list that you wish to copy data off of to your HDD. A summary list of the device's content will appear.
Browse the content and locate the data you wish to copy and select it. Three options will appear.
Highlight and choose "Copy" from the list of options. Another device selection screen will appear.
Highlight and pick your HDD from the device selection screen. The Xbox 360 will then copy the content to the HDD.