Read the book(s)! Then it will all make sense, because they skimped on a lot of important details.
Like the fact that the people who created the map were Lupin, James Potter, Peter Petigrew, and Sirius Black because they were all young friends at Hogwarts and all became animagus to help control Lupin's warewolf at the shrieking shack.
The new Dumbledore wasn't very good either
My mom says I shouldn't talk to conservatives.
