Regular participants in Teams meetings can share screens, mute other participants and perform other actions that are not good in a teaching environment with elementary, middle, and high school students. To restrict their access, perform the following steps.
Before a meeting
You'll need to send out the meeting invite before you can assign roles.
Once you've done that, go to Calendar, click on the meeting you just created, and select Meeting options.
This will bring you to a page, where you'll see a few choices under Who can present? We recommend that you set this to "Only me" unless you have others you want to present during your meeting.
For more information see this Microsoft Support Article.