Remove the following seven screws:

Six 1.6 mm Phillips screws securing the trackpad to the upper case.

One 1.4 mm T5 Torx set screw from its tapped hole near the front edge of the upper case.

During reassembly, do not over-tighten the set screw, as the button will cease to click at a certain point. Adjust the set screw until the movable side of the trackpad has minimal play.