What you need for this:
First, you need to download iTunes 11.1.5. You can download the version for your architecture here. 64 bit / 32 bit
You also need p0sixpwn. Download it by going to this link and selecting your operating system.
Alright, let's get started. Plug in your iOS device to your computer and run p0sixspwn. (Windows users ONLY: Right click on the p0sixpwn executable, go to properties, compatibility, and choose Windows XP and apply it.)
Click jailbreak. If not, you need to be within 6.1.3 and 6.1.6. Anyway, wait for the thing to finish.
If successful and you see Cydia on your home screen, you have done it correctly!
You have finished this tutorial. To learn how to downgrade an iPad 2 to iOS 6.1.3, click here. If you would like to return home, click here.