You need to plug a cable into it from the PC to make it a hub so the other 2 "ordinary" slots work (how did you think it could be USB 3.0 without a USB 3.0 feed from PC)?
http://www.overclockers.co.uk/showproduct.php?prodid=CB-090-AK&groupid=1929&catid=543
Looks near same as the printer cable version.
It comes with one of these cables...