Terrific question. User stories take many forms. But the most reliable way to ensure you've got the success criteria is to have the end-user write it out. While this is the best case scenario, it's sadly not typical. The next best thing is to write out the success criteria and have the end-user validate it for you. In my opinion, the success criteria should be about the "big picture" or the critical path functionality that is needed. You can worry about all the nit-picky stuff later, like what color the conditional formatting should be. Plus, you'll always use your sprint reviews to validate again that you've met the success criteria (part of the Anaplan Way). Here's an example of a user story I built for the "Anaplanwiches". Hope this helps. The success criteria is bold and in red. The sample report is also shown.