How to add a Snackbar in Android

 <?xml version="1.0" encoding="utf-8"?>
 <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity3">
    <androidx.appcompat.widget.AppCompatButton
        android:id="@+id/btnsubmit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="Open Snackbar"
        android:textAllCaps="false"
        android:textSize="18sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
 </androidx.constraintlayout.widget.ConstraintLayout>

 import android.annotation.SuppressLint
 import android.os.Bundle
 import android.widget.Button
 import android.widget.Toast
 import androidx.appcompat.app.AppCompatActivity
 import androidx.constraintlayout.widget.ConstraintLayout
 import com.google.android.material.snackbar.Snackbar


 class MainActivity : AppCompatActivity() {
     @SuppressLint("MissingInflatedId")
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main4)
         val btnsubmit = findViewById<Button>(R.id.btnsubmit)
         val layout = findViewById<ConstraintLayout>(R.id.main)
         btnsubmit.setOnClickListener {
            val snackbar = Snackbar
                .make(
                    layout,
                    "Are your sure to delete",
                    Snackbar.LENGTH_LONG
                ).setAction(
                    "UNDO"
                )
                {
                    Toast
                        .makeText(
                            this@MainActivity3,
                            "Undo Clicked",
                            Toast.LENGTH_SHORT
                        )
                         .show()
                 }
             snackbar.show()
         }
     }
 }