To configure this utility in your gmail account, go to the chrome extensions application store https://chrome.google.com/webstore/detail/vozy-for-google/
Search for applications with the name vozy, You will find two applications
Download "Vozy for Google" clicking on "ADD TO CHROME"
Once you have downloaded the application you will find the Vozy dialing panel in your gmail. To start using it, you authorize Google to have access to your contacts.
You can now start dialing through Vozy from your gmail.