As 3CX user you already have the Webclient or 3CX Phone on computer or smartphone.
That is all you need to get started..
The persons you invite for the video conference don't need to INSTALL ANYTHING.
They receive an email invitation with a hyperlink.
They just open the link in Chrome, Firefox or Edge Chromium and that's it.
People who don't have a computer or don't want to use one can follow the same conference by dialling in on a phone number set by you.
Thay just need to enter the code they received by email to enter the conference.
You already have 3CX and want to start a Webmeeting immediately ?
Fly By Wire