Extract this archive to C:\Program Files (x86)\Electronic Arts\Crytek\Crysis 2\gamecrysis2 or whatever your game folder is.
After extracting you should have a folder called "Textures" in the above path (like this: C:\Program Files (x86)\Electronic Arts\Crytek\Crysis 2\gamecrysis2\Textures)
In order for the new textures to load you need to rename Textures.pak to something else, such as Textures.old.pak or whatever you want, it doesn't matter.