open Cydia, click Manage, Sources, click edit, then add, then type in repo666.ultrasn0w.com let it load reboot and you should be fine.
making sure to use a zero not an "o" in ultrasn0w.
When you'll have to jailbreak it, I assumed you had already done that.
Use redsn0ow 0.8 to jailbreak. Use this link for more info on it it will have everything yo need.