Texturing and using ANT Landscape Add-On

I was making an attempt to create a photorealistic landscape model with very nice textures. But I am having trouble going about texturing and putting materials on the landscape itself, or on certain parts individually. I am also not sure what kind of textures and what not to use to make it look real. It is going to be something more like a mountain range. I don’t know if anyone has really made any use of the ANT add on, but any help would be appreciated.

I don’t understand enough about Blender to understand what all was used in the technique. Could you explain it a bit better? I’ve been self teaching so I don’t know everything.