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I guess I'm a little confused. If you want to add a button or menu to an XCode project, just double-click the .xib file in your project.

At that point, it's pretty much drag and drop (with some extra stuff to link up the outlets and stuff)
 
Also confused

If you're talking about writing an application that has a button in it, then follow ulbador's advice.

But if you're writing an application and you don't know how to add a button (and hook it to your code), then you probably should get a book (maybe Hillgrass) and work through it.
 
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