Your issue is the dynamic sidebar being called is not matching the ID of what is registered.
Matching:
<?php if ( is_active_sidebar( 'sidebar-widgets' ) ) : ?>
<div id="secondary" class="widget-area" role="complementary">
<?php dynamic_sidebar( 'sidebar-widgets' ); ?>
</div><!-- #secondary -->
<?php endif; ?>
Register Sidebar
if (function_exists('register_sidebar')) {
register_sidebar(array(
'name' => 'Sidebar Widgets',
'id' => 'sidebar-widgets',
'description' => 'These are widgets for the sidebar.',
'before_widget' => '<div id="%1$s" class="widget %2$s">',
'after_widget' => '</div>',
'before_title' => '<h2>',
'after_title' => '</h2>'
));
}
<?php get_sidebar(); ?>
tells your template to use the sidebar.php
file.