Setup Alerts to monitor ISP bandwidth usage

HI All,
Total newb here and hoping someone can clarify how I can setup alerts to go out whenever usage exceeds lets say 80% of 1gb/s my ISP has. I have gotten librenms running to where I know email transports are working as I had to turn off port up and down monitoring on some devices as it is not needed for the meantime. ISP device connects to our palo alto FW. I read somewhere that billing could be used. I’ve turned the feature on but I am a bit lost in the details. Hopefully someone can explain or show me how they achieved this. I’ve tried searching with no luck, but if I missed it I would not be surprised. Thanks in advance for everyone’s attention to this!

Look in the alert rules collection there is one for port utilization.