SwiftUI: where to initialize frameworks?

Question

With UIKit and UIApplicationDelegate logic, I used to initialize all the frameworks and stuff in the good old applicationDidFinishLaunching... like this:

@UIApplicationMain class AppDelegate: UIResponder, UIApplicationDelegate {

    func application(_ application: UIApplication, 
                     didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
       Parse.initialize(with: ParseClientConfiguration() {
           $0.applicationId = PARSE_APP_ID
           // ...
       })
       FirebaseApp.configure()
       // etc...
    }

}

I'm now learning how to use SwiftUI, but since there is no more UIApplicationDelegate, and I've never really used UISceneDelegate before, I don't really know where I should do this.

Thank you for your help.