Where can I find this shader you are using in this tutorial? You are saying that it can be downloaded from other course files but I cant seem to find it.
Hey, you can find the CGC_PBR group node in the source file, and it can be appended to any project by going to File -> Append ->BlenderToSubstance_PostApocalypticVehicle.blend -> Node Tree -> CGC_PBR.
Or, if you're using Blender 2.79, the Principled shader will work just as well.
Happy texturing!