Hi Renoki, thanks for buying the tool!
You can't assign different materials to the one mesh, I'll take a look and see how difficult it'd be to implement.
Lighting will affect the meshes you make if you assign a material/shader that accepts lighting. By default, the shader used it unlit so you would have to switch it with a lit shader.
There's no formal documentation yet, but a short guide can be found in the zipped folder you downloaded.
Hope that helps!