That answers it partly, the normal map goes in the layer above the diffuse map and blend is set to multiply. But for multiple maps, how are the layers supposed to be organized (with the diffuse map always the bottom layer)?
Is the layer order supposed to be as follows from top down or does it matter with the exception that the diffuse map is always the bottom layer?:
ambient occlusion
displacement
specular
normal
diffuse
Is blend mode for maps 1-4 except normal map set to multiply, or is normal set to multiply and maps 1-3 (ambient occlusion, displacement, and specular) set to overlay?
Do normal and ambient occlusion maps need to be desaturated first or does it matter that these are not greyscale?