#1 why is knowing the difference between a primary source and a secondary source important?
#2 why would charlie puth's autobiography be considered a primary source and not a secondary source?

The difference between a primary source and a secondary source is that a primary source is most likely going to be more reliable because it came from someone or something that was there when it happened.

Charlie Puth’s autobiography would be a primary source because he is the one writing it. If someone else were to write it they wouldn’t know everything which could change the way that it was written.