Once I paused my game how do I bring up a menu?

For my PauseMenu script I've put in this:

 using UnityEngine;
 using System.Collections;
 
 public class PauseMenu : MonoBehaviour {
     public void PauseGame() {
         if(Input.GetKeyUp(KeyCode.Escape)) {
             if(Time.timeScale == 1) {
                 Time.timeScale = 0;
             }
             else
             {
                 Time.timeScale = 1;
             }
         }
     }
 
     // Use this for initialization
     void Start () {
     }
     
     // Update is called once per frame
     void Update () {
         PauseGame();
     
     }
 }

Now my question is: Once I pressed the Pause key, which is Escape in this script, how do I make a new menu pop up? And also overlapping/removing other GUI formats for a period of time until the Time.timeScale is set to 1 again?