Microsoft Teams is typically installed as part of the Office Suite on University computers. It is also available for smart phones in both the iOS and Google Play stores. Links for all can be found at https://www.microsoft.com/en-us/microsoft-teams/download-app
How do I make and receive calls
Calls using the Teams Phone calling service use standard campus dialing instuctions (9 for outside like, etc). Just use the dialpad in the "Calls" section of Teams,