Before proceeding, unplug and power down your MacBook. Close the display and lay it on a soft surface, top-side down.

Use a P5 Pentalobe driver to remove the six screws securing the lower case:

Two 6.2 mm screws

Two 5.3 mm screws

Two 3.4 mm screws

Throughout this repair, keep track of each screw and make sure it goes back exactly where it came from to avoid damaging your device.