You can't "use" this service, just like that! Integrity has to be preserved, and for that to happen, you need to undertake some actions first. But don't worry, it couldn't be easier!
There are a number of issues to consider when both privacy and security are at stake. As you already know, the beady eyes of many agencies are upon you, ready to intercept at any stage.
The long chain from your computer's manufacturer to your Internet ISP is configured to have weak weak links at every turn. Each of these issues needs to be addressed.
A handy manual is provided for you, wherein you will find the steps to take, and information on how to take them. Please read this first, and follow the easy steps.