Storyboards add a third way to create iOS applications:
Write everything in code
Use Interface Builder to create main windows
With Storyboards the UI is consolidated into a single file with visuals for how each view is arranged together. So, all of the UI work is done in the one place with Interface Builder. View controllers are still an integral part of the workflow, but they are no longer matched with a xib file.
Storyboard – The central concept now in developing iOS user interfaces. Each app has one storyboard (or one per device type for iPhone and iPad apps) and you can use the XCode template to set up a storyboard based app or you can add your own storyboard and then set this up as the main interface in the top level project area. Either way, you will have one file to locate all of your user interface.
Scene – one screen of content (basically a ViewController). Scenes are where you compose your views by adding user controllers and other views.
Note that on an iPad it is possible to see more than 1 scene at a time, for example the master and detail panes in a split-view, or the content of a popover.
View Controller – View Controllers still manage all the behavior of views, now called scenes. Any scene which needs custom behavior or content will still need a custom view controller to manage this. Interface builder is used to set the view controller code file to the associated scene by using the identity inspector and setting the custom class name.
Segue – The transition from one scene to another.You use Interface Builder to add segues between scenes and these replace the code you may have used in delegate methods like didSelectRow:atIndexPath: or in action code associated with a button or other user control.