There are all shapes, sizes and flavors of heatsinks and fans. The one I chose to use is the RDJD P302 model. Its one of the new style bonded, folded fin aluminum heat sinks that's very effective and quite reasonable in price. It comes with a thermal patch already applied, but I removed and used Artic Silver thermal compound instead.
The pictures are ordered in the clockwise direction.
Here you can see the thin folded fins that are bonded to an aluminum heat sink plate. A side view showing the 4 pins, which are inserted through holes in the CPU card. This next picture shows the thermal pad with a piece of protective material on it. Just pull up the pink tab and it reveals the pre-applied thermal patch.
After peeling off the thermal patch, I discovered an unexpected bonus. There is a copper slug bonded to the heat sink plate. This is good news as copper transfers heat much better than aluminum does. You must clean both the heat sink and the CPU core of all thermal paste and patch material before applying new thermal compound. A final cleaning with some alcohol on a rag is also recommended. I squirted on a small amount of Artic Silver thermal compound. Remember a little goes a long way; you only want a very thin layer of the compound. If the layer is too thick, you will lose some of the heat transfer capability of the compound. And actually the amount you see there on the copper slug was about 13rd more than I needed, and at $12 - $15 dollars a tube, you don't want to be wasting it. I spread it around using an Exacto knife; a razor blade would work just as well. It looks like its on their pretty thick but I had to turn off the lights because they reflected off the aluminum heat sink plate. You could just as easily apply the compound to the CPU core as well. Just remember you want a thin coat.
Now you are ready to attach the HSF to the CPU card. Line up the holes on the CPU card with the pins on the HSF and slide it through. Press them together to get a good seating of the CPU core into the thermal compound. The next couple of steps will be determined by what kind of mechanism your HSF came with to lock it to the CPU cartridge. The RDJD P302 requires that the back plate be installed on the CPU card; some HSF's will have their own requirements. You slide the locking bracket over the 2 pins in the left of the pic. The bracket is marked with the word UP so you know which way to put it on. Slide the other 2 pins into the holes in the bracket. You can see that they are at a different angle than the other 2 holes. Once you have them in the bracket holes, you just push up the right side of the bracket using the raised tabs on that side and it locks into place. The completed unit all ready to be installed into your computer :o)