Reporting part-time earnings while on benefits - any advice?

I picked up part-time shifts as a delivery driver and I am confused about how to report them. The form asks for gross earnings, which I do not see until later. 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.

Keep everything in writing and save the confirmation numbers. It saved me later.