I believe the 20GB internal hard drive is part of the media XL pack only, so if you haven't got that then you won't have a hard drive. I bought a small (physical size) 32GB USB sticks for £8 and copied mp3 files onto that and plug it into usb port in Mini, works ok although moving between albums seems to be a bit of a pain (standard LCD screen).
As an aside I was surprised to find that standard sound system only has 2 speakers (in front doors), didn't check before ordering but expected at least 4!
