If I upload a course and start to navigate that course how do I toggle back to the ride screen to see speed, time ect. I don't know if it's possible. I can't find any information and I'm afraid of losing Ride data if I start pushing buttons
Just use the up and down buttons on the left side like normal. Navigation is just a function of the device that is done on top of the normal recording.
You won't stop navigating by changing views, it's actually a pretty deliberate series of button presses you have to go through to stop navigating.