825i Windshield Wiper Kit Install

Finally got a JD glass windshied for my 825i.

The problem I'm having is with the windshiel wiper wiring kit. The little bit of instructions that came with it say to use a wiring snake and run the wiring harness from under the right rear ROP and out the left front cross brace on thr ROP.

Anyone got any good advice on just how to do this??

Thanks