simple explaination - - https://steemit.com/toolkit/@sndbox/earn-steem-by-upvoting-how-curation-rewards-work-on-steemit

And here is what I think explains it in somewhat detail. https://steemit.com/curation/@miniature-tiger/an-illustrated-guide-to-curation-from-the-simple-to-the-complex-with-real-examples-from-past-posts-part-1

The one from @miniature-tiger I think explains it to the level you are interested I think.

No reward needed if you felt I would have won. Give it to the next best answer or donate to @newbieresteemday