RN 204 - New user previously owned/used device

So purchased this 4 bay model, new to NAS completely to then find seemingly nothing available now for it. Managed to get and install Plex Media Server by googling but, is there any other software available for it anywhere?

Had no software install discs, just the device and 4 x 1tb drives and the power cable.

Presuming just wasted my cash and beyond using it as storage device via network (usb too, or does that require some software to connect direct and use it just as storage)?

Would have liked to get some kind of cctv setup for it as well as use for other purposes

Into photography so any good storage management beyond using Plex (installed mainly for music and perhaps movies) would be useful.

As to any help advice in regards if it is of any use as a device still.