A watchOS app may include more than one screen. When this is the case, choose the navigation model that best meets your needs: page-based or hierarchical. You can’t use both models in one app.
Hierarchical navigation is well suited for master-detail interfaces or for presenting a navigable list of options. It can also make it easier to extend your app and add new content later. When users tap an item in a hierarchy, a new screen appears that displays details about that item. With vertical page-based navigation, users can also navigate quickly between detail views for different rows using the Digital Crown or by swiping vertically on the detail view.
Page-based navigation is an alternate way to present a flat collection of information in which all items are peers. In page-based navigation, each item is displayed on a single page that scrolls vertically. Users swipe horizontally to navigate from page to page, and dots indicate their place in the set of pages. Because navigating through a large number of pages can be time-consuming, limit the number of pages you include in your interface.
Use modal sheets to extend your interface, if necessary. Although you must choose a single navigation style, you can present a modal sheet from either style.
Focus on essential content. Your watchOS app should complement your iPhone app, not mimic it. Including too many pages of content makes navigation time-consuming and confusing for the user. Design your app for quick and convenient interactions.
Avoid creating hierarchies deeper than 2-3 levels. Shallow hierarchies make it easier for users to find what they want quickly. Including more than 2 or 3 levels of information might cause the user to lose their place during navigation.
For developer guidance, see WKInterfaceController.