All I would add to what bolox has posted is to make a back-up of the CloD folder just in case. If you mess up the patching process you can delete the folder and copy the original back in. It's by no means the worst mod install I've seen and if you follow the video you should be golden.

Applying patch 4.0 has caused some confusion,as it comes as 2 files,one a zip and one an executable.Just run the executable and make sure you re-start the game after EVERY patch install as instructed.