Use this guide to replace the keyboard cover.
Use a spudger to gently pry off the bottom cover of the phone.
There is a piece of rubber covering the microphone. This may fall off while removing the bottom cover. Do not lose this.
Use a spudger to gently lift up the keyboard interface from the bottom.
Peel the keyboard up until it is freed from the phone.
Gently lift the key pad away from the phone.