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

My hours change every week at my new part-time job and I am afraid of reporting wrongly. This is my first time dealing with any of this. 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 made the follow-up calls so much easier.