From the Dash Cam app, you can start the recording from the Dash cam app by tapping on the red button. Once started, hit the home button on the top of the Overdryve. From the home screen, you can tap on the Navigation app and start it

The Dash cam is still recording. To go back and view to the Dash cam app, tap on the square on the bottom of the screen, and then tap on the dash cam app. You can toggle back and forth by tapping on the square. As long as you don't close the app or tap on the red record button, it will remain recording.