Registering sidebar

/**
 * Register widgetized area and update sidebar with default widgets
 */
function thirteenmag_widget_areas() {
	register_sidebar( array(
        'name' => __( 'Top Sidebar', 'thirteenmag' ),
        'id' => 'right_sidebar',
        'before_widget' => '<div class="single_widget fix">',
        'after_widget' => '</div>',
        'before_title' => '<div class="widget_title"><h3>',
        'after_title' => '</h3></div>',
    ) );
};

add_action('widgets_init', 'thirteenmag_widget_areas');