So your dealer is able to get the harness in before the manual?
The manual has great drawings for wiring & cable routing. Assuming you've got the luxury of taking your time, no it doesn't look to be a tough job to install a new harness. Explaining the details in a text message is a different story. Did someone make the mistake of removing the original harness before they had the replacement ready to install?
If you have the harness before the manual, and you gotta install it, spend some time looking it over, and perhaps come back with a specific question.