Tapping a menu item should cause the CarValet app to behave similarly to tapping a tab bar item. If the content is not showing in detail, tapping should cause it to show. If the content is already showing, then unlike in the tab bar, tapping should do nothing.
Although you have only created three menu items, there are really five menu states, since
Cars shows the list of cars. Table 11-2 lists what is in the detail view for each state.
The detail view is a navigation controller, so you can push, pop, and even set the array of view controllers. Two of the detail items, About and Images, ...