You can turn on "Side Button Icons" to see a physical representation of the buttons function on the screen while in-ride.
Here are the steps to turn On the Side Button Icons:
Tap on "Settings" from the Home Screen
Scroll down till you see "Side Button Icons"
Toggle it "On"
You can see the side button icons on the Karoo screen when in-ride.
Note: This can be enabled/disabled anytime from the Settings app.