substance painter coat in pbr metallic shader

Hi, 

I'm trying to add a coat to my metallic shader in Adobe Substance Painter (steam edition) but I can't find any documentation or tutorials on how to do this. I tried adding all the coat related channels to my shader and enabling them on a new layer but it did nothing 😞 

is there something I'm missing? I remember allegorithmic having really good tutes and documentation so it's puzzling that I can't find anything with a google search 😕😕

thanks for any help in advance