During the installation you'll be asked to enter the hostname of the Jitsi Meet instance. If you have a FQDN hostname for the instance already set ip in DNS, enter it there. If you don't have a resolvable hostname, you can enter the IP address of the machine (if it is static or doesn't change).
This hostname (ot IP address) will be used for virtualhost configuration inside the Jitsi Meet and also you and your correspondents will be using it to access the web conferences.
# Open a conference
Launch a web broswer (Chrome, Chromium or latest Opera) and enter in the URL bar the hostname (or IP address) you used in the previous step.
Confirm that you trust the self-signed certificate of the newly installed Jitsi Meet.