How do you report hours that vary week to week? - 16 weeks in

I picked up part-time shifts as a retail manager 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. Who can I ask without risking my claim?

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

The claimant handbook has worked examples for part-time pay. Mine was clearer than the phone line.