You will need thermal paste to reassemble the heat sink later. Do not try to reuse the thermal paste.

The heat sink is held down by two plates. The right plate, covering the CPU, has 4 screws. The left plate covering 4 smaller chips, has 2 screws.

To unscrew the right plate, carefully pull up warranty label to expose screw. remove 4 screws.

To unscrew left plate, remove two screws. Carefully detach black cloth tape from heat sink, leaving it attached to the left cooling fan.