How can I setup Jitsi server to Ubuntu vm? What should I enter as 'The hostname of the current installation'?

How can we setup Jitsi server on our Ubuntu machine? Is there any guide?

I think I found it https://jitsi.org/downloads/ubuntu-debian-installations-instructions/.

In the final step what am I supposed to enter?

The value for the hostname that is set in Jitsi Videobridge installation. The hostname of the current installation: [What should I fill here]

Should I enter the machine’s public IP?

Look at https://jitsi.org/qi.

When installing you should enter the DNS of the machine where you are hosting your deployment, like ‘meet.jit.si’.

What if I don’t have a DNS? In that case can I enter the machine’s public IP?