Only drives that are formatted in FAT32 or Mac OS Extended (Journaled) will be compatible with the USB port on the AirPort Extreme. NTFS and exFAT are not supported.
Unfortunately, we have few Windows users here, and I am not one of them, but one of the Apple Support documents below provides 3 methods for PCs to connect to a drive at the AirPort Extreme. The other provides general information about format compatibility.
Hopefully, one of the PC guys will post soon to provide additional information.
I believe that you have 90 days of free phone support with a new Apple product, so you might want to explore that route as well.