Linux Network UPS Tools Setup

Power failures have been wrecking my server, so I recently plugged it into a USB UPS.

The problem is that the power failures last longer than the UPS battery can handle so I need the server to shutdown when the UPS battery is low.

I have been looking into the Network UPS Tools software and it seems to be exactly what I need although I find the documentation to be very unhelpful and difficult to follow.

Has anyone had success in installing it and if so; what are the most important steps to ensure a basic shutdown command on low UPS power?