Grass under terrain??

Hello there again,

I have downloaded a lot of Nobiax textures andd ssome other stuf. Im having a hard time using them. They come with 4 textures, difuse, normal, translucency and specular. I have no idea how to set all 4, but even if I just set it up with just the normal, or spec on the difuse and load it into the terrain editor I get some crazy results...

One is that if I load the grass, I get grass on the terrain and Below! Another is that if I load as trees they cant be rescaled...

I realise im going about this all wrong, but I cant find much on these packs for unity execpt for other peoples unanswered questions. I hope this one does get an anwser, for it is driving me kindda mad now, after 12 hours of fidleing...

Many thanks once again to you all!

Cheers.