The following steps will prevent meeting participants from accessing other user controls when employees are using Teams to conduct meetings.  

1.    When setting up a Teams meeting, click Options, then more options

2.    The Who can Present setting Is set to Everyone, click the dropdown

3.    Select Only organizers and co-organizers

If the organizer of the Teams meeting is still having difficulty managing attendees, there are two other settings that may help.  These settings will stop the attendees from having access but will allow the organizer to give access to users, as needed.