将基于Xcode视图的应用程序转换为基于导航的应用程序？

Newbie question: is there an easy way to convert a view-based app to a navigation-based app? I have an existing app sample that was created as a view-based app, and need to be able to create additional viewcontrollers that can be nested. The app is currently using presentModalViewController calls and nibs to display windows. Trying to change these to pushViewController calls results in the views not being displayed. So I'm assuming it's because the pushViewController needs to use a Navigation view. Thanks in advance!Newbie question: is there an easy way to conver