You should use the class Teams site as your primary channel for communication in this class. The teaching team will use it to send messages to the entire class (i.e., all class announcements will come through Teams), as well as communicating with individual students or teams as necessary. You are encouraged to use Teams messaging for communicating with your classmates, as it provides an “encapsulated” and professional environment for this purpose, outside of personal social networks. It also easily allows you to initiate audio or video calls/meetings with other classmates on a one-on-one or group manner.
The one exception to using Teams as a platform for communication is if you have to discuss personal matters with the instructor. For this purpose, you can use private messaging in Teams, or set up an audio/video call, but you may also use email if you prefer.