You probably just need to add that page to your Garmin device. Or possibly just add those particular fields to any screen you desire to see them on.
Not sure what you are talking about for eTube. Did they make an app for riding. I thought eTube was just for setting up and checking your Di2.
edit...
okay, just looked up Shimano E-Tube Ride. That's a new one for me.
https://bike.shimano.com/en-US/e-tube/ride.html