AppDelegate.swift

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.

    /// ↓ ADD THIS ↓
    if let rootWindow = window {
        let iPhoneXSize = CGSize(width: 375, height: 812) /// if you're running this on an iPhone X, delete this line...
        //let iPhone8Size = CGSize(width: 375, height: 667) /// ...and uncomment this line

        Projector.display(rootWindow: rootWindow, testingSize: iPhoneXSize)
    }
    /// ↑ ADD THIS ↑

    return true
}