How do I connect phone bridge?

How do I connect phone bridge?

Ive got the Premium account. From what I have read, I need to download Twiolo, which looks like an online Skype-type service. Is this correct? Does Phonebridge cost extra (or is it a separate add-on app?)

So Phonebridge uses the online calling, rather than my mobile? I have read something about using an adaptor?

Is there a way to click on the phone button in my Leads contacts, and make calls through my phone?