Step 1: Download redsn0w 0.9.15 dev 3 using our Jailbreak Programs Tool
Step 2: Download your device firmware using our iOS Versions Tool
Step 3: If you are using Windows, run redsn0w as administrator, in compatibility mode. Then browse and load the ispw file downloaded on step 2.
Step 4: You will have to choose some options. Make sure install cydia is checked.
Step 5: Put your phone in DFU Mode.
Step 6: Your device is jailbroken, but it`s tethered mode. You need to press Just Boot from Extras.
Your device is now jailbroken!