You will be invited by your teacher to join an online meeting at a certain time if you have the Ms Team app loaded on your PC or phone (this will be a notification).
Make sure that you do the preparation required for the meeting (if relevant)
Five minutes before the meeting starts open Ms Teams and open Calendar; find the meeting, click on it and hit the “Join” button. The meeting will be displayed on the calendar (same as the Outlook calendar). Click on Join,
The next dialog box allows you to turn the microphone on/off and your camera on/off.
NOTE: If your teacher has planned a lecture (and not a meeting) he may turn everybody’s microphones and cameras off by default. If this is the case, you can get his attention using the chat function. If necessary, he will then change the microphone settings so that you can communicate verbally as well.