starting core data and iCloud

hi, i worked with core data and i created an app based on it. now i want to make it icloud enabled. however after searching online i found many approaches to hooking up a core data app to iCloud. some of the approaches uses UIDocument and some stores the persistanceStore in the cloud. i'm totally lost to which approach i should use. Anyway, i wanna start from scratch. i'm searching for a book/tutorial/videos to learn how to use core data and icloud together. i want the sources to be able to teach me by creating a simple core data app and adding it to the cloud. i searched so many books but as i said they don't follow the same approach or they just provide code and not practicing (like creating a simple app and update it in each chapter). Apple's documentation is really rich but there's no application while reading them to see them in action. So any suggestion? Thanks1