Before installing the Alaska, you need to attach two clips to its base. You also need to install the metal wires that hold the fan. In Figure 10 you can check the Intel clips in place.
After that, just put the backplate on the solder side of the motherboard, put the cooler in place and fasten the four screws (with springs) that hold the cooler in place.
In Figure 12, you can see the Alaska installed in our case, with the fan installed.