With the laptop upside down, disconnect the power connector visible in the RAM bay. Turn the laptop right side up again.

Disengage 3 connectors from the top of the motherboard:

The video connector near the top left.

(The small connector adjacent to the video connector need not be disengaged.)

A small connector at the bottom right corner of the motherboard

The 2nd hard disk bay connector towards the bottom right of the motherboard.