After becoming contacts, you have two ways to make free call：
1. in the contact interface for details click on the "free phone", you can call this contact free.
2. When you chat with your contacts, click on 【+】of the extensions box, you can make a free call.
1. How to create a conference?
1).Clice on the Conference botton at the Contact screen.
2).Clice on the Create a conference botton to create conference.
2. How to join a conference?
You can join a conference by serching the ID of the host.