Ok,
So firstly you must rename the file config-production.json as mentioned in this post OpenHab Cloud Installation. and next edit your system snippet.
this is my local configuration:
{
"system": {
"host": "192.168.137.246", //you openhab2 installation ip
"port": "8080", // the 8080 openhab2 installation port
"protocol": "http",
"logging": "info",
"subDomainCookies": false
}
Don’t forget "registration_enabled": true.
(web interface) openHAB UUID and openHAB Secret respectively in /var/lib/openhab2/uuid and
/var/lib/openhab2/openhabcloud/secret.
If you would to access your openhab2 installation directly without the 8080 port, install Apache and enable mod_proxy check the link below
How To Use Apache as a Reverse Proxy with mod_proxy on Ubuntu 16.04
About the outside network you should configure the Port Forwarding parameter in your router. ‘there are a lot of options like DDNS, Remote Access’.