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

I picked up part-time shifts as an accounts payable clerk and I am confused about how to report them. I have read a lot of threads here and could not find my exact situation. Pay posts on a different day from when I work. Do you report when you earned it or when you were paid?

I estimated and then checked my pay stub. When there was a small difference I wrote to the agency to correct it.