Make sure you establish all the basics before taking him out with the cattle if he is green broke. We had a 2yo mare where i used to work who knew next to nothing undersaddle, she was quite green and only had the Clinton Anderson groundwork done with her. The owners son took her out to work cows and she came barreling back to the barn, riderless, thru the fence. So...make sure he is confident with your basics before anything.
Work on the gaits, walk trot and canter, whoas, steering is another good one. Make sure he is very responsive to YOU. This will make him good for kids and for working cows.