Yup. You got it.
Applying thermal paste is not as hard as a many people think. ONe important thing to remember is (LESS) is better.
1.) Clean both surfaces. (Heat Sink & CPU Die) use rubbing alcohol.
2.) After CPU is in socket, put a rice size dot of thermal paste on the center of the CPU die. With an old credit card or similar object, start to spread out the thermal paste evenly over the whole die. If a little more is needed add it now. Then scrap the thermal paste extremely thin over the die. It may take a few times to get the hang of it. The thinner the better.
3.) Carefully lower Heatsink, attach.
The whole idea behind thermal paste is conductive heat transfer. There are microscopic impurities in the heatsink and cpu surface. These hinder heat transfer. So the thermal material is used to "patch" these impurities, filling them in. Allowing for better conductive heat transfer.