There are fundamental principles that apply to the use of every GPS system and associated moving maps, like
1) Check that the database is up to date
2) What data blocks do you want
3) Understand the difference between bearing, track, and direct track
4) When to use ETE vs ETA
5) How you can use ground speed to manage flight profiles
6) What map scales are appropriate for each phase of flight
7) Advantages and disadvantages of the direct to function
8) Lateral vs vertical navigation
9) Managing navigator induced cockpit distraction and strategies to ensure that a good lookout is maintained
10) Strategies to recover from a sudden navigator failure.
11) Strategies to use the navigator to most efficiently and safely fly an unplanned inflight diversion.
I would suggest that if you asked the average PPL instructor the above questions they would really struggle to provide sensible answers.