Using maps exported from WM to apply textures

[Utogi]

I've been searching around the internet the past couple days on how to take the different maps that I export from World Machine into Terragen as a guide to apply a texture (such as using the flow map as a guide to overlay a gravel texture on the height map). I have the Height map for importing the terrain, and I have grey scale images that show where different materials go such as snow and erosion deposits.
So my question comes in two parts:
1. How do I use a grey scale image as a guide for texture placement and
2. How do I apply textures such as an image of dirt and and possibly a normal map that goes with it?
I've attached a picture of what the overlay looks like in WM, but I'm rather unfamiliar with shaders in Terragen so if someone could suggest how to do this that would be great.

Edit: Apologies if this thread is in the wrong section, I'm relatively new to these forums.

[Dune]

First of all, welcome to the forum.

Basically; you import the images in an image map shader, it's default is at projection Y (down) sot that is good. Then you set the size same as the terrain you're importing (probably in another image map shader). Use that as a mask for a surface shader later in the line, under base colors, where you can apply all sorts of (smaller) displacements and color, set altitude and slope restraints if needed.
If you put a color adjust shader in between them, you can further adjust the coverage of the image map.

I hope this helps you on your way.