Use an iFixit opening tool to lift the screen from one of the vertical sides of the phone and continue gently prying until the screen is loose enough to safely remove.

The damaged screen is connected under the screen assembly with a small plastic brace; remove this with an iFixit opening tool.

Be careful around the home button. It has little tabs to keep it in the frame, but they will break if the adhesive isn’t loosened with age or heat.