If you want to configure notifications from your Exchange Calendar, be it your personal calendar, shared calendar, or group calendar, you should go to your Outlook settings: click the gear icon on the ribbon and then click “View all Outlook settings” at the bottom.
Go to “General => Notifications” and find all the notification settings, like in-app and desktop pop-ups, for incoming emails and events.
In-app and desktop notifications in Exchange Calendar
Other notifications in Exchange Calendar
In “Calendar => Events and invitations” settings, you can find default reminder settings that will pop up in Microsoft Teams.