Step 1: The first thing you will need to do is download Eavsi0n for Windows, Mac OS X or Linux. This can be done by using one of the links below.

Step 2: With Evasi0n downloaded you will need to extract it. On Mac OS X you will find a .dmg file that upon being clicked you will be able to drag the files to your desktop, but one Windows you will have a ZIP File that can be extracted by right clicking on it and then clicking the extract to folder option.
After the Evasi0n Jailbreaking tool has been extracted find the Evasi0n app / .exe file On Windows you will need to right click on it and then click the Run as administrator option. On Mac OS X 10.8 Mountain Lion and above you will need to hold down the control button on your keyboard, click the Evasi0n app and then the Open option to get past Gatekeeper.