Please take a look at my guide for setting up Joplin Server. It is for arm, but the general things will work for you, too.
You can't connect from your local network and the internet at the same time, because then the URL doesn't match with the set Base URL in the config in one of the cases (exect you set up a local DNS, but that's an other topic).
In your Router you have to forward Port 80 and/or 443. You connect over regular http(s) to your server, which internally routes the traffic to port 22300.