UConnect feature: Press and hold for a couple seconds the center button on the back of the steering wheel on the left side. This will activate the UConnect similar to pressing the button on the rear-view mirror. Once this is activated, you can use the center button on the right side of the steering wheel similar to the second Uconnect button on the mirror. This seems to only stay active until you are done making a call, then the bottons revert to controlling the sound system.
Nav feature: Just like above, but this time press and hold the center button on the right side of the wheel. You will see a little steering wheel icon appear on the Nav screen (bottom right next to the clock) and the rear buttons now control the nav system, with the ability to scroll through menus and select destinations just using the steering wheel controls. I timed this and the controls will revert back to the default controls for the sound system after 30 seconds of non-use.