Isn’t there a matching upholstered panel about a foot by several inches inserted in your dash top, immediately in front of the driver? If so, it’s what your manual is referring to, and is simply held down by velcro. Pry it up carefully with something that won’t damage the upholstery; if it’s never been removed, the velcro may yet hold it quite strongly.
Besides a tech port back near the engine, one should also be under that dash panel. Service techs need to be able to hook into the system when working either at the engine or from the drivers seat.
Joel