The TC is not designed as a file store.. if you do so think very carefully how you will backup the TC.. it has no inbuilt backup except a manual archive to a USB disk plugged in which is very slow.. TM cannot backup a network drive.. overall the TC is unsuitable.. and Apple has nothing else on the market to help you.
A server or NAS is really what you need.
But you can try your luck.. are you feeling lucky.. !!
As for a fault description .. it doesn't work properly.. sadly very little I can do with that.
I strongly recommend you buy the usb to ethernet adapter apple sell for the air.
It is cheap and whilst not as good as real ethernet will allow you to do wireless setup without using wireless.
Plug in and press and hold reset.. once it flashes rapidly go to the airport utility and setup the TC.
If your existing router is ok.. set the TC to bridge. If you have a cable modem.. plug in the TC as router, and reboot both with a 15min wait for the cable modem to reset.