How do you report hours that vary week to week? - first time posting

I picked up part-time shifts as a retail manager and I am confused about how to report them. This is my first time dealing with any of this. Pay posts on a different day from when I work. Did anyone get an overpayment notice from a mistake?

Thanks for writing this out. I went through something close to it 8 months ago, and it settled down once I kept a simple log of every call and form.