Notifications in teams are really important. It is your responsibility to make sure that you have them switched on and are being regularly checked.
Each channel has a notification bell (top right of the team window). The default will be a bell with a strike through. Please tap on this bell and select ‘all new messages in the channel’. You will need to do this for each channel you are a member of.
To view the main notifications tab press the hamburger (top left) and tap notifications.
I suggest that you first of all set ‘Quiet Hours’ this disables notifications for selected times and days.
Receive notifications - Always
Switch on all other notifications
Scroll down and switch on ‘mute while in meetings’ this will stop others seeing your notifications if you are in a live lesson.