Can anyone help me get my plex server working correctly?

My plex works great when I’m within my own home but I can’t seem to get the “Not available outside your network” to go away and I don’t know where to start troubleshooting. I’ve clicked on the “Learn More” button but am still having difficulties. Any help is appreciated.

Here is a good place to start. It’s a long read but very informative.
https://support.plex.tv/hc/en-us/articles/200931138-Troubleshooting-Remote-Access

If I had to guess, I’d say you don’t have the port forward in your router.

The router that I’m using is the C2100T from Centurylink. Does this help? I went thru that article and tried some of the things in there but no luck. Maybe I’m missing something? Not sure how to set up the port forward either. Would be nice to finally get this working…