Reporting part-time earnings while on benefits after 8 years as a security officer

I picked up part-time shifts as a security officer and I am confused about how to report them. There are 8 people counting on me, so I am trying to be careful. The form asks for gross earnings, which I do not see until later. Did anyone get an overpayment notice from a mistake?

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