Help a noob

Katjat

Hello polycount, I'm an art newbie and I've just started learning Zbrush. It's the first 3d software I've worked with and since I'm unfamiliar with most techniques used for sculpting, could you give me a hand in completing this 3d model for a project? By completing, I mean you point me in the right direction, maybe to the right tutorials (there are so many out there, it's kind of confusing) for the following things:

1. How do I make the ribbons on the rocks? Mesh extract seemed like a good idea at first, but there must be a better way to do it
2. How do materials work in zbrush? Basically how do I make the rock look like a rock, grass look like grass, etc
3. Should I create the textures from polypainting, and if so, do I do it before or after adding the surface details on the model? 

This is what I've done so far

 
This is the concept art

Brian "Panda" Choi

1) Mesh Extract, or in a standard 3D software art package like Maya, Modo, Max, etc, make the low poly versions of the mesh and then bring it into Zbrush.

2) Materials are generally run by MatCaps.  I would look into documentation and free MatCaps to look for what you want.  You can apply them like you do Polypaints, but your "mRGB" or "M" button must be on during application, "m" being "MatCap" in this case.

3) You can if you want if you're planning to keep this all as just a high poly mesh.  Low poly meshes for a game will need UV mapping of a lower poly mesh and texture painting on said UV map.  You do it after your Zbrush sculpt is finalized.  The resolution of the polypaint is determined by vertex color, so the higher the point count, the denser the "canvas" of tthe model.  

I'd aslo recommend upgrading to Zbrush 2018.  There's a lot of noob friendly features there that will be msot helpful for you, including Sculptris.