Your administrator should have set up your Salesforce account with Ringio. Once that is done you will see a little box on the top right corner with Ringio click to call:
Enter the email and password you have setup with Ringio and click on the Sign in button
Once you are logged in, you can go to any lead or contact you have in salesforce and click on the phone to the right of the number.
Ringio will first call your phone, wait for you to answer it and then call the number of your contact.