Hi,
I don't have a NavAll Star but did own one of it's predecessors (NavAll One). I did find a photo of the installation manual if you can call it such. Maybe the units are similar. It is worth a try.
The NavAll Star is sort of a generic Chingling unit sold by "he who must not be named" under his own "brand". You should be able to find additional info on this forum.
You might even get lucky and have @Coolcat drop by in this thread. He has installed and supported quite a few Stars back in the days.
HTH