Do not try to completely remove the front panel assembly from the rear case, as there are several ribbon cables still attached at the top of the iPhone.

Once the clips have been released on the bottom and sides of the front panel assembly, pull the bottom of the assembly away from the rear case.

Open the display to about a 90º angle, and lean it against something to keep it propped up while you're working on the phone.

Add a rubber band to keep the display securely in place while you work. This prevents undue strain on the display cables.