Important Note: In order to make and receive phone calls from other telephone numbers you'll need either a business voice subscription or an active phone system/calling plan added to your office 365 account
Step 1
In Microsoft Teams, click Calls
Step 2
Either type the Name/Number you want to call or dial the number using the Keypad
Step 3
Click Call
Step 4
Please allow a few seconds for the call to be connected, when you ready to leave or end the call click Leave