Lay out the harness along the left side of the motorcycle. The end with the long yellow wire goes to the rear. There is no need to tape or zip-tie anything in place at this time, though you can certain do so if you want to. I always wait to tape or zip-tie until after I've gotten everything installed. The basic routing is shown in the following photos.
Ambassador without turn signals
Thanks to Kevin Kelly for sending me these photos in a private e-mail. In Kevin's own words:
These are the pictures of my 1969 Moto Guzzi 750 Ambo. I have owned it since 1975. I never took it apart until 2010 and doubt if anyone else ever has.