Create a new file:
nano /etc/apt/sources.list.d/jitsi-stable.list
Input this content to the file to get access to the jitsi repository:
deb https://download.jitsi.org stable/
Save the file and run this command to install jitsi:
apt install jitsi-meet
If the installation manager asks for a hostname, take the full domain name of your jitsi installation you want to use.
For example: jitsi.yourdomain-comeshere.com
The jitsi installer will automatically setup itself if you are using nginx- if you want to use a webserver like apache you have to take setup steps which are not explained here. Maybe you will get a SSL Error if you try to join the site - than its needed to create a valid SSL Certificate using certbot for example and apply it to the nginx configuration of your site normally located at : /etc/nginx/sites-available.
After an alteration of the nginx configuration you have to restart nginx service:
service nginx restart