Required fields for caption

[Dunai]

I was mucking around with the code for many hours and didnt get anywhere. I dont know much about php/mysql either. But i was to have required fieds for captions eg:
When somone uploads a photo, they need to fill in "Rider", "trick" and "Location" i know theres the extrea fields with the file information but i want to put them on the caption instead of in the file information part. It would be great if somone could point me in some sort of direction. Thanks heaps
-Ian