1TB My Book on AirPort Extreme - Snow Leopard

I have the External HD plugged into the AirPort Extreme via the USB cable. Under AirPort Utility, the Extreme shows the Disk, however it shows 0 MB and I cannot access the HD to save any files to it. Someone please tell me how stupid I am and give me the easy instructions to get this bad boy working. Thank you!

Whats the model number of the drive?

Most of them come preformatted for windows for fac it requires reformatting

heres the instructions