Things You'll Need
Instructions
Connect the USB flash drive or the FAT32 formatted hard drive to one of the USB ports on your PlayStation 3.
Navigate to the "Settings" menu on the XMB dashboard and select "System Settings" from the list. Scroll down and select the "Backup Utility" option.
Select the "Back Up" option--it will be the first one in the list. You will be reminded that Trophies must be backed up elsewhere and the system will ask if you wish to continue; click "Yes." The system will then ask you to confirm that you want to back up the data to an external storage device; select "Yes" again. Choose the destination for the backup data, whichever device you connected to the PS3, and press "X" to start the process. Allow the backup process to complete before disconnecting the storage device.