How to write remember me (cookie) in PHP

I made a login page. so I can already login to another page. then on my login page I need to put a checkbox and PHP on my mind. so what part of these codes do I need to put in the "remember me" codes? please, help.

this is login1.php

<?php
session_start();
//database connection
$servername     = "localhost";
$username       = "root";
$password       = "";
$dbname         = "lala";

// Create connection
$link = mysql_connect($servername,$username,$password) or die("Could not connect");

$db= mysql_select_db("$dbname",$link) or die ("Could not select database");

$login = $_POST['login'];
$password = md5($_POST['password']);
$rememberme = $_POST['remember_me'];

$result = mysql_query("SELECT * from admin WHERE working_id = '$login' and password = '$password'");
$count = mysql_num_rows($result);

if($count==1)
{
    //check remember me is on or off
    //if off then session login
    //else add cookie

    $_SESSION['username'] = $login;
    $_SESSION['password'] = $password;

    $result1 = mysql_query("SELECT * from admin WHERE working_id = '$login' and password = '$password'");
    while($row = mysql_fetch_array($result1)){
        $_SESSION['gp'] = $row['gpType'];
    }
    header('Location:dashboard.php');
}
else 
{
    $_SESSION['username'] = NULL;
    $_SESSION['password'] = NULL;

    ?>
    <script type = "text/Javascript">
    alert("Sorry , wrong username or password");
    setTimeout("location.href = 'abc.php';");
    </script>
    <?php
}
?>

      

        
        
        
      

    

this is my html

    <p><input type="password" name="password" value="" placeholder="Password"></p>
    </div>
     <div id="form2">

    <p class="remember_me">
      <label>

        <input type="checkbox" name="remember_me" id="remember_me">
        Remember me 
      </label>
    </p></div>
    <div id="form3">
    <p class="submit"><input type="submit" name="commit" value="Login"></p>
  </form>
  </div>