Lay out a soft cloth on your workspace to prevent scratching the screen in this and future steps.

Pry open the back casing using the soft plastic opening pick.

Be careful of the Power & Volume Key ribbon on the left side just next to the volume key. The ribbon is exposed and could be damaged with the opening tool.

Carefully pull the back casing apart from the rest of the phone with your hands. Because the casing is glued to the rest of the phone, this step may require some force. Don't be alarmed if the casing flexes a bit.

You may need an iOpener to loosen up the adhesive. Check out the iOpener Instructions for info on how to use it.