Plug your USB drive into the Mini and you'll probably get a box pop up after a couple of seconds telling you the USB has just been plugged in and the capacity of the drive etc. etc. now go to Menu > Installation Menu > External Harddisk > Format External Harddisk and you should now see a list of the USB devices, select the one you want (most probably only the one anyway) and press OK now press RED to format and it'll ask do you really want to format, select yes and click on OK and the process will start, it'll take a few mins now depending on how big the HDD is etc. and then it'll tell you once done.... Once finished that should be it and your drive is now seen by the Mini.