Can anyone tell me how to use the terraintex shader that comes with GS7?

I can use terraintex3, and another terrain shader I got from the web, but with terraintex I get an all black level. I must not be assigning the textures correctly, but I'm not sure how else to do it.

Also, how many textures can I use with fx_terraintex? My shader from the web uses 4. Is there a way to use 5 or 6?

Thanks for helping a lost....and not to bright....newbie!