Reporting part-time earnings while on benefits (update)

I picked up part-time shifts as an event coordinator and I am confused about how to report them. I have read a lot of threads here and could not find my exact situation. 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?

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.