Do you want to know how to play the front passenger display or the rear entertainment through the main car speakers?
It's pretty easy. Just look for the 'Listen' button on the center screen.
Unfortunately, the front passenger can only listen to their glove compartment audio using a Bluetooth headset. There's no headphone jack like the ones in the rear seats.
The best way to read the owner's manual is online. You can download it from your Mopar account. There's also a Uconnect manual, but I haven't used it much since most of the important stuff is in the Wagoneer manual.