Apply a small amount of thermal compound, about the size of a grain of rice, on the corner of each the cleaned thermal plates on the motherboard.

Using a clean plastic card, carefully spread the thermal compound evenly over the surfaces of each thermal plate.

You need to clean the thermal plates on both the component and the motherboard, but you only need to apply thermal paste on the motherboard thermal plates.

Avoid applying too much or too little thermal compound, as it can impede crucial heat transfer. Once spread, the compound should be about as thick as a single sheet of paper.