Android 10.25 Screen Issues - No sound

My Android 10.25 screen does not show the NTG screen and has no sound. This is how I went about and fixed it for good. This was on a 2010 Mercedes Benz W204 C63 but the concept could work on any android auto screen. The issue was that the original OEM screen, NTG, was not showing up, allowing me to select AUX which is the correct setting to play sound from Apple CarPlay. Found a power wire was never hooked up allowing the NTG to connect to the screen to visually select an output. The screen just kept saying "No Signal" which was a clue to help diagnose