How to implement a stack data structure into a linked list?

I'm still learning how to use LinkedList, in my CSCI 1302 course, correctly so let me know if I am doing something wrong. I want to implement a stack data structure using the operations push() and pop(). I still need to build the driver class, but I was hoping someone could show me where I could implement these two operations within my code.

import java.util.*; 

  public class myStack {


    private class Node 
    {
      public int data;
      public Node next; 

      public Node(int data)
      {
        next = null; 
        this.data = data; 
      }}

   public LinkedDesign() //Linkedlist constructor
   {
     head = null; 
   }
   public void add(int keydata) //add new value to the end of linked list 
   {
     Node temp = new Node(keydata);
      Node current = head;

    if(head == null)
     head = temp;
    else
    {
     while(current.next != null)
     {

      current = current.next;
     } 
     current.next = temp;
    }
 }


       public void print()
 {
        // from head to tail, print each node's  data
  for (Node current = head; current != null; current = current.next)
  {
   System.out.print(current.data + " ");
  }
  System.out.println();

 }

       // toString(): print data in the linked list
 public String toString()
 {
  Node current = head;
  String output = "";
  while(current != null)
  {
   output += "[" + current.data + "]";
   current = current.next;
  }
  return output;
 }

}