I need help blocking users from joining scheduled meetings without the organizer's permission.

I have the following problem, the teachers are scheduling their classes and the students are being able to join the conference videos without the teacher giving permission. I need to shield this. I need to find a way, if any, that only the organizer of the video conference will allow the participants to enter. I even researched the configuration of the meeting lobby using the “meeting options” option, but all the settings I made were in vain.

For example: I have a team whose name is Turma - 141 the teacher will create a meeting for this team to conduct an online class at 3:30 pm. Then he will click on CALENDAR> NEW MEETING. You will enter the necessary settings and use the "add to channel" option so that information about the meeting is displayed on the channel.
After that, he can open the option "Meeting options" and configure the lobby, however in "meeting options" it does not give me the right to make people join the meeting only after the organizer's entry. With that, students are entering the meeting without the organizer being present.