Add a note on tutorials with imaginative functions

[coool9]

Some very new coders might wonder what is the OnPlayerDoThing, etc.

[adib-yg]

I don't understand. what should we do?

[coool9]

Just a hint somewhere when imaginative functions are used that will give undefined symbol error if copy pasted

[Y-Less]

Or better, a note that you should actually read and understand things.