In general you have two options, either use Demodesk for your calls or another service. You can choose between between several options in the settings of your desired Event type:
To use your own audio setup choose disable audio in the Dropdown menu.
If you already know that your customers prefer one option over the other, we recommend to set the settings accordingly to make it as easy as possible to join a meeting. Phone dial-in is especially helpful if your customers use older browsers and don't regularly hold meetings on their computers.