In the project navigator, select Main.storyboard. Xcode then brings up a visual editor for storyboards, called interface builder.

A storyboard is used to lay out views and transition between different views. As we use a single-view application, the storyboard already includes a View Controller.

Next, we will add a button to the view. The bottom part of the utility area shows the Object Library, as shown in the following screenshot:

Drag the Button object from the Object Library to the view:

Stop dragging and move the button to the area of your choice. Double-click on the button and rename it Click Me.

Next we will add a few lines of code to display our message. In the project navigator, you should find the ViewController.swift file. We will be adding a method to the already present ViewController class. When this method is called, our code will tell iOS to display a certain message.

Now let's code our method. This is what our method looks like:

@IBAction func showMessage(){ 
let alertController = UIAlertController(title: "My First App", message: "Hello World", preferredStyle: UIAlertControllerStyle.Alert) 
alertController.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler:nil)) 
self.presentViewController(alertController, animated: true, completion: nil) 
} 

This is what the finished work will look like:

Now we need to connect our Click Me button in the storyboard to our showMessage method. This part is easy; we click on Main.storyboard, where we have displayed our screen.

Press and hold the Ctrl key on your keyboard, click the Click Me button, and drag it to the View Controller icon.

Release both buttons, and we see a pop-up message with the showMessage option. Select it to make a connection between the button and our function:

That's it! If everything is correct, we can now run our app perfectly when we click on the run button: