To append the Model the Floor Choose File -> Append -> Choose the proper blend File -> Choose Material, then "Penrose_Floor_Large_8192" or "Penrose_Floor_SuperLarge_16384" Material. This Choice Depends on the Power of your Computer; the large Texture Set (8192x8192 Pixles) is recommended for smaller Graphic Cards, the super large Version will run proper on heavy Systems. Or you can choose the smaller Version for Test renders, and then use the large one for the final render shot. Assign this Material to your Floor. Then go to the UV-Image Editor and choose choose one of the image Textures. Now you need to UV Unwrap the Plane of your Floor. The most simple way is to switch to a view perpendicular to your Floor Plane, then choose "Project from View" for UV unwrapping. Now Tweak the Scale and location of your UV Map according to your needs along the Penrose Floor Image Texture. For further information of how to UV Map Meshes to Images, please check the Blender Wiki. The Full Description of the Shader can be downloaded here, but it is also packed within the package.