Chapter 5, Pickers : WKInterfacePicker is the only programmatic way to work with the Digital Crown. You’ll learn how to set one up, what the different visual modes are, and how to respond to the user interacting with the Digital Crown via the picker.
Chapter 6, Layout : Auto Layout? Nope. Springs and Struts then? Nope. Guess again. Get an overview of the layout system you’ll use to build the interfaces for your watchOS apps.