You didn't give a model number. I initially found the info for the BMW model, then found the Nissan version. I'm going to assume that the only difference between the units is in installation, while the basic operation is essentially the same for each version.
Audiovox AMBR1501AVW MediaBridge
Audiovox MediaBridge Kit A-MBR-1500-BMW
Audiovox Nissan Mediabridge Bluetooth Streaming Kit (AMBR-1500-NIS)
Point of clarification... Was your objection to the instruction manual you found based on the way it's presented? If so, here's a clean copy of the manual:
https://www.voxxintl.com/docs/common/A- ... HON_OM.pdf
And I found this as well...
Operating the Audiovox MediaBridge Kit A-MBR-1500-BMW for BMW and Mini Cooper Vehicles