Develop Your iOS Application with Storyboarding
As you develop your iPhone or iPad application, you use Interface Builder to graphically add user interface elements to each one of your views in the storyboard. (Just think of views as containers for displaying what you see on the iPad screen.) In this context, user interface elements include things like controls, images, and placeholders for content you'll display.
After you've added the elements you need, all you have to do is fill in code where it's needed. If you've used Xcode to program in the past, you'll find that you have to write a lot less plumbing code — code that is specifically designed to do things like launch view controllers — and, in some cases, no plumbing code at all.
Typically, you lay out the entire flow of an application early on in the development process, but for learning all the basics of developing an app with Xcode, you might do it in stages. That means that for your first app, you'll do some of the storyboard stuff now, but wait until you understand everything better to storyboard the rest of your app.
When you do more apps, you'll be ready to start with the storyboard and design your application flow the way it should be done — in one fell swoop.
Selecting the MainStoryboard_iPad.storyboard file in the Project navigator opens that file in the Interface Builder editor. Although all this may seem a bit daunting at first, after you go through it once, it will seem like old hat.
In the olden days (pre-storyboards, and thus pre-iOS 5 and pre-Xcode 4.2), you used nib files to define your user interface one view controller at a time. The term nib (with its corresponding file extension .xib) is an acronym for NeXT Interface Builder, a bit of software originally developed at NeXT Computer, whose OPENSTEP operating system was used as the basis for creating Mac OS X.
A nib file is a special type of resource file that you use to store the iOS user interface you create with the Interface Builder editor. Storyboards are actually just a series of connected nib files. Remember, View controllers manage what you see on the iPad or iPhone screen.