Set the location of the light source by moving the pointer at the Direction panel. Decreasing the radius raises the height of the light.

The relief data can come from the  Source Texture or the Mask. Smooth the heightmap by increasing the Pre-Smoothing parameter.

Scale the height values of the heightmap with the Amplify value.

There are two light colors: The one of the direct light (Primary Color), which comes from the light source and is angle-dependent, and the color of the ambient light (Secondary Color), which is constant over the texture.