Register Multiple Dynamic Sidebars for Wordpress

functions.php

function sidebar_widget_areas()
{
register_sidebar( array(
'name' => __( 'Left Menu', 'sidebar' ),
'id' => 'left_sidebar',
'before_widget' => '<div class="single_sidebar">',
'after_widget' => '</div>',
   'before_title' => '<h2>',
   'after_title' => '</h2>',
) );

register_sidebar(array(
'name' => __( 'Sidebar Top', 'sidebar' ),
'id' => 'sidebar-top',
'description' => __( 'An optional widget area for your sidebar top.', 'freedombd' ),
'before_widget' => '<div class="top_sidebar',
             'after_widget' => '</div>',
       'before_title' => '<h2>',
            'after_title' => '</h2>',
   ) );
 
       register_sidebar( array(
'name' => __( 'Promo Sidebar', 'sidebar' ),
'id' => 'promo',
'description' => __( 'An optional widget area for your sidebar left.', 'freedombd' ),
'before_widget' => '<div class="promo_sidebar',
                  'after_widget' => '</div>',
                  'before_title' => '<h2 style="display:none">',
               'after_title' => '</h2>',
   ) );
}
add_action('widgets_init', 'sidebar_widget_areas');

sidebar.php

<?php dynamic_sidebar('left_sidebar');?>

OR

<?php dynamic_sidebar('promo');?>

Example page

<div class="sidebar floatright">
<?php if ( ! dynamic_sidebar( 'left_sidebar' ) ) : ?>
<div class="single_sidebar">
<h2>Sidebar Title</h2>
<ul>
<li><a href="">List Item</a></li>
<li><a href="">List Item</a></li>
<li><a href="">List Item</a></li>
<li><a href="">List Item</a></li>
<li><a href="">List Item</a></li>
<li><a href="">List Item</a></li>
</ul>
</div>


<div class="single_sidebar fix">
<h2>Sidebar Title</h2>
<ul>
<li><a href="">List Item</a></li>
<li><a href="">List Item</a></li>
<li><a href="">List Item</a></li>
<li><a href="">List Item</a></li>
<li><a href="">List Item</a></li>
<li><a href="">List Item</a></li>
</ul>
</div>
<?php endif; ?>
</div>

Calling Code

<?php get_sidebar();?>

NOTE: Call the above function where you want to see  sidebar in index.php or other page