A newly released feature, meeting hosts are now able to mute all meeting participants with the click of a button.
When in your meeting environment, navigate to "full screen" from the top panel.
From here, you will see a "mute all" button located underneath the call recording button.
This is a quick and easy way to mute your participants. They will, however, still have the ability to unmute themselves from their end. If this happens prematurely, you can click "mute all" again.