Use a T5 Torx driver to remove the 13 screws securing the trackpad assembly:

Nine 5.8 mm screws

Four 4.9 mm screws

These screws all look similar—be careful not to mix them up.

Adding a little blue threadlocker to the screw threads during reassembly can help prevent the screws from working themselves loose over time.

Install the screws loosely at first, and then check the trackpad alignment before tightening them down.