iOS - Navigation bar has no back button

Question

I am currently using a walkthrough view controller to show a "getting started" carousel when you first open my app. Once you select get started, there are two buttons at the bottom that direct you to login as one of two types of users:

However, As you can see here there is no back button to take you back to the page where you decide what type of user you are. Here is the code I am using to segue:

override open func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    let NavViewController = segue.destination as! UINavigationController
    let NextViewController = NavViewController.topViewController as! LoginViewController
    if(segue.identifier == "client") {

        NextViewController.request = 0;
    } else {

        NextViewController.request = 1
    }

}

In addition, I have added titles to all of the other view controllers in their viewDidLoad() methods. If anyone has an idea of why the back button isn't showing, I would greatly appreciate your help!

Answer 1

Question has been answered by Grundewald. Solution: The navbar needs to begin before the initial segue. Thank you for your help!