RiCe_KiLlEr

ok im sitting here looking at the instructions for the mounting bracket assembly for my vortech supercharger. and on the instructions im looking at the belt diagram for the 2000-2004 mustang. I see where the vortech idler (ribbed) goes and how to relocate the factory idler. the only thing im not getting is i dont know where to put the (supplied plastic idler) I went and looked on my car and i dont see where it would go. also it says nothing about where to put it on the instruction except on the belt diagram. This is driving me crazy. can someone please help me out