When to use a class over a function?

I've just become half decent at functions but still struggle with classes. I've got a couple working mostly with chatgpt help.

1. How would you explain the difference to a 5 year old?

2. How do you know when you'll need to use a function over a class?

3. How do you know when you'll need a class over a function?

4. Do you usually start building functions and then later realise "Oh I can bundle these into a class to make life easier in the future." ? (I do)

Thanks in advance to anyone that answers.