WebinarAdministrator Pro is a powerful, features rich, easy to use Joomla webinar manager extension. It allows you to create and host webinars and meeting rooms inside your website.
WebinarAdministrator Pro integrates BigBueButton or Jitsi Meet or OpenMeetings servers. Because of that, It's mandatory you have a Bigbluetutton or Jitse Meet or OpenMeetings servers.
If you don't have one, you can install them (all of them are OpenSource) or use free testing servers offered by BigBlueButton and Jitsi Meet.