Remove the four rubber screw covers from encircled locations.
Using a #0 tri wing screwdriver, remove the screws previously hidden below the rubber covers.
If you have difficulties finding this screwdriver, it is commonly sold as a Nintendo Gameboy/Wii screwdriver.
Pry the case open using iPhone tool (as shown), fingernails, small flathead screwdriver, etc.
Be mindful of location and magnitude of applied force, so as not to damage the case.