I have no idea what to do?

I'm 13 years old and in my state you can work at 14 yrs old. My friend told me she applied too late and that I should apply now for jobs, except I have no idea what I'm doing. I don't know about resumes, how to make one, what I should wear for the interview, 'cause it feels weird to apply for a job at Dairy Queen or Market Basket and show up in a fancy outfit. It's all just very confusing. I have no idea what to do and if someone could please spare some time and explain it, or give me a link or something that explains it all that would be great.

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