Just like stunt doubles for actors in action movies, pronouns are stunt doubles for nouns. They're ready to take actions when nouns are not there!
Do you want to know how to talk about an action or event that happened a few seconds, a few years or even hundreds and thousands of years in the past or future?
Noun is the most populated country in the world of grammar. It is the first stepping stone of learning any new languages. So without further ado start learning!