A noun is a person, place, or thing. A pronoun is a word that takes the place of one or more nouns. The pronouns I, we, he, she, it, and they are used in the naming part of a sentence.
Bobby is eating popcorn.
I am eating popcorn.
Sophie, Anya, and I are playing soccer.
We are playing soccer.
Eric, Jessica, and Philip are going to bake a cake.
They are going to bake a cake.
Emmanuel plays the violin well.
He plays the violin well.
Rosie floats peacefully in the pool.
She floats peacefully in the pool.
The cat climbed up a tree!
It climbed up a tree!