Step 1: You can call a contact from the interaction panel. First, select Voice as a channel.
Step 2: The panel highlighted below will display the number you are dialing from and the contact number you are dialing. If None/Private is selected, the click-to-dial button will be greyed out.
Step 3: As soon as you select an outbound flow, the click-to-dial button will turn green and you can dial out.