Caution: Ensure your laptop has been powered down.
Close the laptop, flip the laptop over, and pop off the back small panel with a flathead screwdriver. The panel will be hanging by the hinges once open.
Grip the heat sink from the sides and carefully lift it up to remove it.
Heatsink is a device used for absorbing heat and necessary to remove to reach the fan.
At this time there will be a whitish powder between the heatsink and the CPU. This powder below the heat spreader is degraded thermal paste. DO NOT wipe away this powder unless the thermal paste will be replaced upon reassembly.