Twitch affiliate with no business?

I wanted to ask what happens if you have already earned around 10-20 + € with twitch before applying for a commercial. What happens then

Then I wish you that the tax office doesn't send you mail.

You can also enter this in retrospect, but report it soon and have an overview of your finances and in black and white

Do I just need a business? And what else? Because I'm 15 and I plan to register a parent as a business owner. Do I have to pay attention to anything else for twitch affiliate? Except for business