Navigation Bar is an optional element in <iPhone View> (to create, right click <iPhone View>, select Add Element, and select Navigation Bar).
Navigation Bar would tyically contain 2-5 Navigation Bar Items, each acting as a clickable button. To add a new Navigation Bar item, right click Navigation Bar, select Add Element, and select Navigation Bar Item).
For example, in the application below there are two Navigation Bar Items ('Top Trends' and 'Public Tweets'):
Sample modeling: Twitter on iPhone:
For best results, use the Firefox browser..