If you search you will find instructions... took me forever to find the amp but once I did I can just reach up and behind and adjust the knob.
Radio is okay but I liked the Monsoon in my 02 Camaro better, even though I blew about 6 subwoofer speakers in it.
Best advice for stock... go into settings on the diagnostic menu and turn off that setting that keeps the unit from over driving speakers,,, turn off eq and adjust non eq settings to your liking.
All here if you search...
I find myself leaving radio and sirius off and listening to the exhaust serenade me...