It’s helpful to think of pronouns as a “relief pitcher” in baseball. A relief pitcher comes in to take over for another pitcher who may be getting tired. Well, pronouns act much in the same way. They help in not having to reuse the same nouns repeatedly. See a simple example below:
Mike went to the store to buy milk. Mike had to walk, since Mike’s bike was broke. The store was a short walk from Mike’s house. While there Mike bought chocolate milk, since that was Mike’s favorite.
From the example above, the proper noun, Mike, needs a “relief pitcher.” Time to use some pronouns.
Mike went to the store to buy milk. He had to walk, since his bike was broke. The store was a short walk from his house. While there Mike bought chocolate milk, since that was his favorite.
See examples of pronoun usage below from my playthroughs of various video games. MAKE SURE TO TURN ON "CLOSED CAPTIONS" TO VIEW NOUN EXAMPLES.
Note: Look to the RIGHT of each clip to be aware of the game's ESRB Rating.