For example if you look at this exercise here
The first argument in .findById, is not an object, how did people approaching this exercise know that?
You haven’t stated it in the exercise, and every exercise up until this one the function took an object as the first argument.
You haven’t linked to any mongoose documentation.
How can you just throw questions at people and expect them to know that answer if you haven’t told them?
Also when you click "get a hint’ you get a 404!!!