The word good is an adjective. Use the word good to modify a noun.
Frisky is a good dog.
My brother is a good ball player.
The word well is an adverb. Use the word well to modify the verb and tell more about the action.
Sam does well in school.
Jim plays baseball well.
Use the adjective good when modifying a noun. Use the adverb well when telling more about the action of the verb.
It’s your turn. Decide if you should use good or well in this sentence: Mary always listens _____ in class. Did you figure out that you need an adverb? Good for you!