Locate the 1.5 x 7mm Phillips #00 screw at the bottom right of the keyboard housing.

Remove this screw. Note that this is the only 1.5x7 mm screw in the entire laptop, so it is very important to keep track of it.

Place a screwdriver or other firm tool with a fine tip inside the hole to the left of the screw hole. Push all the way to the left to unlock the slide.

It will take a good bit of force to move the slide, as it unlocks a series of clips underneath the trackpad plate.