Google Meet is a video conferencing app. It is the business-oriented and educational version of Google's Hangouts platform and is suitable for businesses of and classrooms of all sizes. Google Meet integrates with G Suite versions of Google Calendar and Gmail and shows the complete list of participants and scheduled meetings.
You need to log in to Google with your staff or student email and password to be able to use it.
See this video tutorial on how to setup and use Google meet.