The additional JVB is basically the same as the one that is configured by default on the same machine as Jitsi Meet, with the only difference that it connects to the IP address of the Meet machine (and not to localhost) and also it has a different nickname.
Apart from these two things, I think there are no other changes. You can install JVB on the second machine, then compare its config files to the ones of the internal JVB on the Meet machine, and change these two things (IP to connect to and nickname). Of course, the Meet machine has to allow connections to 5222 tcp from the new JVB machine.
P.S.: And of you are asking specifically for the scaling - there are a lot of different scenarios and setups, depending on lot of things - your network setup and whether you are in the cloud, etc. If you have issues with the scaling, please specify what you are using and what breaks
First of all, I really appreciate your kind consideration.
I am planning to have one JMS with 3 JVBs (all in the same vLAN).
I’ve installed first JVB and set the domain as JMS hostname during the installation
configured “sip-communicator.properties” based on same configuration in JMS; However, I’ve changed these:
org.jitsi.videobridge.xmpp.user.shard.PASSWORD (same as JMS)
currently I have “tcp 0 0 meet.dkserv:xmpp-client vb1.******:41458 ESTABLISHED” on JMS
JVB 2022-12-25 12:14:38.531 SEVERE:  HealthChecker.run#175: Health check failed in PT0.000095S:
java.lang.Exception: Address discovery through STUN failed
Despite disabling videobridge service on JMS, I can run a meeting even while JVB server is down!!!
systemctl status jitsi-videobridge2
● jitsi-videobridge2.service - Jitsi Videobridge
Loaded: loaded (/lib/systemd/system/jitsi-videobridge2.service; disabled; vendor preset: enabled)
Active: inactive (dead)