FirstVCReceiveReady.swift

import UIKit

 class FirstVC: UIViewController {
   @IBOutlet weak var FirstVCLabel: UILabel!
   
   override func viewDidLoad() {
     super.viewDidLoad()
     NotificationCenter.default.addObserver(self, 
                                            selector: #selector(doSomethingAfterNotified),
                                            name: NSNotification.Name(rawValue: myNotificationKey), 
                                            object: nil) }
   
   func doSomethingAfterNotified() {
     print("I've been notified")
     FirstVCLabel.text = "Damn, I feel your spark 😱"
   } 
}