GOOD is the adjective, as in "He is a good golfer". It describes a noun, an object, a person.
WELL is the adverb, as in "He plays golf well". It describes an action, doing something.
Read these sentences aloud using "well" instead of "good":
01. He's a good speaker.
02. She's a good driver.
03. He did a good job.
04. They had a good dinner.
05. He paints good pictures.
06. She is a good dancer.
07. He was a good cook.
08. She had a good sleep.
09. He made a good speech.
10. All the members of the choir were good singers.