In the top right corner of the Teams application, click "..." next to your initials
From there click settings, and select "Notifications and Activity" from the listed categories
From here scroll through the notification settings and adjust them as you desire. The notification settings are broken up into the following categories:
General - The main notifications settings, includes sound and display
Chats and Channels - Manage notifications specific to chats and channels
Meetings - Adjust notifications received about meetings
Presence - Track a person's status and get notifications when their status changes
Calendar - Manage notifications for calendar invites and activity
Apps - enable, disable, and adjust specific app notifications