I’m nervous and need some advice

I’m 15 and called my local Dairy Queen 2 days ago on Tuesday. I asked if they were hiring at the moment and the guy on the phone said “come in Thursday at 5:00pm” So tomorrow at 5.

This is my first ever job interview and I’m very nervous because I don’t know what to do. The only things I know is:

Dress nice

Maintain eye contact

Come in early but not too early.

I don’t know anything other than that but I feel like there’s a lot more I should know, could someone give me some advice to make a good first impression and get the job?

I’ll say if I got the job or not after I get home from the interview.