How do you report hours that vary week to week? (update)

I picked up part-time shifts as a forklift operator and I am confused about how to report them. Pay posts on a different day from when I work. Do you report when you earned it or when you were paid?

Report honestly and keep your stubs. An honest small error is much easier to fix than a missing report.

The claimant handbook has worked examples for part-time pay. Mine was clearer than the phone line.