Use the regular Office 365 Calendar and not the calendar built into Teams. Here is a video that goes through the steps:
How to use the Teams App on your mobile device.
This will particularly interest Administrators and District Staff
System Audio
How to play a video or audio file in Team Meeting
Posts vs Chat
What's the difference and when to use them
Calls
How to make video and audio calls in Teams
Calls - Advanced
Setting up your Voicemail and Speed Dial
Files
A brief introduction to using this feature to share with other Members of your Teams
Files - Advanced
Copy files from OneDrive to Teams
Calendar
How to add a calendar event in Teams and in Outlook: What's the difference?
Screen Record
Record your screen in Teams for lessons and demonstrations