The upper case is secured in place by magnets.

Grip the top edge of upper case above the keyboard and lift straight up to release it.

Don't try to completely remove the upper case just yet, as it's still connected to the rest of the laptop.

Lift the front edge of the upper case up and away from the laptop, taking care to not strain the keyboard and touchpad ribbon cable underneath.

During reassembly, lower the upper case onto the lower case until the magnets snap into place and it lays flat.

Check that the upper case sits flush around the entire perimeter. Any gaps between the upper and lower case near the display could cause damage to the display as it closes.