activate custom sidebar widgets

You would register the sidebar in the functions.php file with something like this:

<?php
register_sidebar(array('name'=>'custom-content',
 'before_widget' => '<section>',
 'after_widget' => "</section>",
 'before_title' => '<h3>',
 'after_title' => "</h3>"
  ));
?>

And Use it in your theme like this:

<div class="contents">
<?php if ( function_exists(dynamic_sidebar(1) ) ) : ?>
    <?php dynamic_sidebar(custom-content); ?>
<?php endif; ?>
</div>