Instructions
Formatting the Flash Drive
Connect your USB flash drive to one of your Windows PC's USB ports.
Hold the Windows key and press "E" to open the "Computer" menu.
Right-click the USB flash drive icon and select "Format."
Select "FAT32" from the "File System" drop-down list and click "Start."
Click "OK" to confirm you want to format the device. This may take several minutes.
Eject the USB flash drive from your computer when finished.
Configuring for Xbox 360
Insert the USB flash drive into one of your Xbox 360's USB ports.
Power on your Xbox 360 by pressing the guide button on the center of the Xbox 360 controller.
Select "System Settings" under the "My Xbox" section of the Xbox 360 dashboard.
Choose "Memory" and select the "USB Storage Device" option.
Select "Configure Now" to configure the entirety of the space on the device for Xbox 360 data. Select "Customize" to manually adjust the amount of space on the device reserved for Xbox 360 data.