To install the cooler, the fist step is to prepare the backplate, inserting screws in the available holes according to the socket used by your CPU.
After that, install the backplate on the solder side of the motherboard, put the cooler on the CPU and screw the four thumbnuts. Easy? Not at all. The access to the thumbnuts is so narrow that we had to remove the motherboard from the case in order to install the TherMax Eclipse II, even considering our case has an opening in the motherboard tray, giving access to the solder side of the motherboard. Only after installing the heatsink on the CPU is that you can install the fans.
In Figure 15, you can see the TherMax Eclipse II instaled in our case.