remember anything on the usb stick will be wiped off.
Plug usb stick into the back of the box and then press the menu button on the remote. Select Setup -> System -> Storage Device -> Initialise -> usb stick -> press red button
Once initialised press red button on remote and select plugins -> MountManager and make sure your usb stick is listed. It also needs to show Mount:/media/hdd - if it doesn't then press the green button and then using the left/right arrows on remote change mount until /media/hdd is highlighted and then press the green button. The box will then restart.