Insert an opening tool pick under the screen, starting at the top of the phone.

Slide the pick around the entire perimeter of the display to break the adhesive.

There is a cable on the right side of the phone (the side with the volume buttons), which connects the screen to the rest of the phone. Be careful not to damage this cable.

Once enough adhesive has been removed, you should be able to separate the screen by gently lifting it from the left side of the phone.

While not necessary, applying a gentle heat to the edges of the display with a heat gun or iOpener will weaken the adhesive.