Reporting part-time earnings while on benefits - 23 weeks in

I picked up part-time shifts as an administrative assistant and I am confused about how to report them. I do not usually post, so bear with me. 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.