See that "BaseWhite" thing on your screen? (It's in the screenshot, at least.) I'm sure you already know how this comes in.
But the thing is, if the texture is not included in a material file it won't work unless you put it into one. If it doesn't work even then then there's something wrong with the material file.
So for example you'd be putting in "rockMat" (With caps. It's caps sensitive, don't forget that!) where you'd want a rock sort of texture.
If the texture still isn't working even if it has its own material file something must be wrong with it. I'd suggest using another mesh's texture, though, like the default rocks and trees or something else you've downloaded. Or maybe even try to find a way to fix it, like finding the texture for the house (If it wasn't included in the download it's not there. So sadly, you'd have to go back to my suggestion about borrowing other mesh's textures.) and taking that to use in a new material file. You can use my example.
Hope this helped as well!