Catholic learning about Judaism stuff.

Hey guys, I’m a Catholic just trying to learn about Judaism so these might be stupid questions.

Correct me if I’m wrong, but you have like over 600 commandments to follow… do you know them all by heart? There are so many, is it difficult to not break them just from day to day life? Or are they sufficiently obscure so that they’re not something that you can accidentally stumble across?

Does Judaism have any sort of unifying governing body like we have the papacy? If someone is a sufficiently bad Jew is there a method of excommunication?

Are all Jews supposed to follow the same rules? If so, what accounts for the various type? Orthodox vs Hasidic, etc.