How to create dialog series 1 basic - kotlin 3

MainActivity.kt

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        findViewById<Button>(R.id.btn).setOnClickListener {
            val dialogFragment = MyDialogFragment()
            dialogFragment.show(supportFragmentManager, "my_dialog")
        }
    }
}