First things first, push the silver button on the front side of your key fob to release your emergency key from the fob. Then, use a small flathead screwdriver and insert it on the side, where the emergency key meets the key fob.
You can set the top part of the key fob aside for the time being and just focus on the bottom. Pick up your flathead screwdriver, insert it in the seam where the front panel of the fob meets the rear panel, and give it a light twist. That should pop the key fob right open!