New prius owner/questions with screen options! Help!!!

I just bought a 2013 prius 4 with the solar roof package this past weekend. I researched this car for a long time and love it so far! I have a couple questions with my screen settings and Hoping someone can help or can point me in the right direction.

I can't figure out how to make the screen brighten and dim when it's day/night. And my "default/home" screen is the navigation screen. I've managed to get it to split with my audio screen but I'd love my main screen to JUST be my audio screen and only view the navigation screen when I'm utilizing the navigation. Please help! Thanks everyone!