Using the plastic opening tool, pry open the body of the phone, starting at the bottom of the phone (this tends to be the easiest place to start).
Double check to make sure the SIM card is removed from its housing. You will not be able to pry open the body of the phone if the SIM card remains in its housing.
Continue by sliding the opening tool around the perimeter of the phone. You should hear multiple clicking sounds as you complete this, indicating the clips are becoming unlatched.
This may take a few tries to get correct. Don't give up if it doesn't work the very first time.
Put the red casing aside and remove the motherboard from the front casing of the phone by carefully dislodging it from its two clips near the top of the phone.
As you can see, the rubber keypad is attached to the front casing. Gently remove it from the case by pinching any part of it and lifting. Don't worry, it isn't attached too firmly and is easily removable.