How to enable more than 2 caller in Jitsi Meet on Ubuntu 16.04

Hi Everyone,
I’ve installed succesfully jitsi meet on a VPS with Ubuntu 16.04 with Apache 2.0 and it work fine with video-conference between 2 callers. I know that a 2 callers conference is managed P2P and a multi-caller conference need specific configuration. I’ve dig around the forum to understand what kind of configuration should be done but with no luck. I’ve set to false the “enable” property in the “p2p” section of the MYDOMAIN-config.js under /etc/jitsi/meet folder. I’ve read thet should depend also if the server is behind NAT or not: my server has the public address directly on the interface. What else should be set up ? Another question: I don’t understand if videobridge is running or not and eventually how to start it.

Thanks for any hints.