If your power button is malfunctioning this is what you need to replace it!

A replacement power flex cable

A small philips heads screwdriver

A platsic opening tool

A tweezer (Not necessary but can come in handy)

In this guide i also use a scalpel, I simply forgot to take a picture of it, most of the work can probably be done with the opening too instead, it's just a bit trickier.