"Well" and "good" mean essentially the same thing but have different grammar rules. If I ask you how you are doing, you should say "I'm doing well." The phrase "I'm doing good" is technically incorrect, even though we say it all the time. An easy way to think of it for now is like this: things are good, actions are well. The food is good. The music is good. The store has good books. The food is cooked well. The musician plays well. The store stocks their books well. "Nice" can mean the same thing as "good" sometimes, but usually it means the same thing as "kind." A person who gives you directions is "nice." A professor that gives you an A instead of a B is being nice. "Fine" usually means something is acceptable. If I say "how are you?" and you answer "I'm fine." it means that you're not feeling bad, but you're not feeling spectacular either. If you are doing a project, and it's not amazing, but it works, then the project is "fine." Think about it like this. From worst to best, something can be: terrible, bad, fine, good, great. I hope this helps.