Faux stone exterior siding

Hello, I'm Bill and I need help understanding these directions. I'm installing this faux stone about halfway up my house. I stripped the existing siding off to the 3/8" plywood. Then put up a woven house wrap. Then where the stone is going I put 1/2" Durock on. Now where I am confused is do I need to still apply a "scratch coat" before I "butter" the stone then install or can I just butter it and install.



I'm attempting to copy and paste a link of the product instructions.



http://www.menards.com/main/bargaini...structions.pdf



Thank you in advance for any and all help you can provide.



Bill

Kansas City