The side buttons are located here, on a small and delicate ribbon cable that wraps around from the left side of the frame to the inside, under the motherboard.

Insert the tip of your tweezers under the contact pads. There is a small gap that is hard to see that will let you get your tweezers under the contact pads to provide some leverage.

Once the contact pads are lifted up, gently pull the ribbon cable up with your fingers to release it from the adhesive holding it to the frame.