When the adhesive has been adequately heated, use the edge of a plastic opening tool to gently pry the plastic display frame away from the front glass panel.

Run your tool under the plastic display frame to separate it from the front glass near the home button area.

If the panel does not separate from the frame, reheat the area you are working on and try again. The adhesive must reach a certain temperature before it will yield, and reaching that point may require reheating the area several times. Once the adhesive has reached the right temperature, it should be fairly easy to run a plastic opening tool under the frame to separate it from the front glass panel.