http://www.slate.com/articles/video/video/2015/06/apple_icloud_everything_you_need_to_know_in_order_to_back_up_update_and.html

It's understandlable if thoughts of the iCloud send you into a foggy haze of confusion. Do backups happen automatically across your Apple devices? How much storage are you unknowingly using to run apps and hold media? What will happens if you’re planning to take the leap from an iPhone 4S to the 6 or 6 Plus? In the video above, we break down the basics of iCloud, iCloud drive, and iCloud photo library so you can upgrade and sync worry-free.