Working with Schemes and Projects in Xcode
Xcode 4 introduced schemes: a powerful way to control how you build, debug, test, analyze, profile, and deploy your application. Discover how to efficiently test your project, get a greater understanding of the Xcode build system, learn to use static libraries with iOS, and see how to configure your project for maximum productivity.
WWDC 2012 - Session 408 - iOS, macOS