Meetings can be added to calendar events, so that a meeting link is automatically available for all attendees to join. The event in your Google calendar will contains a link to the meeting - you simply need to follow the link to join the meeting.
To join a meeting in a Google Calendar event:
Click on the event in your calendar
Click on the Join with Google Meet button
The meeting will launch and you will be able to see how many other people are currently on the call. Click on the Join Now button to join the meet call.