Step 1: Pull out the keycaps where the screws installed and remove the screws. (As the picture shown)

 

Step 2: Then you will be able to take out the top part of the keyboard and next, unplug the battery cable and daughter PCB cable. 

 

Step 3: Take out the silicone bottom pad. 

 

Step 4: Unscrew the screws on the daughter PCB.