How to create custom taxonomy?

I have been reading a custom taxonomy tutorial and started implementing the same steps that were mentioned but I am not getting the exact display that required. I have pasted this code in functions.php.

add_action( 'init', 'create_cw_hierarchical_taxonomy', 0 );
//create a custom taxonomy name
function create_cw_hierarchical_taxonomy() {
$labels = array(
'name' => _x( 'Topics', 'taxonomy general name' ),
'singular_name' => _x( 'Topic', 'taxonomy singular name' ),
'search_items' => __( 'Search Topics' ),
'all_items' => __( 'All Topics' ),
'parent_item' => __( 'Parent Topic' ),
'edit_item' => __( 'Edit Topic' ),
'update_item' => __( 'Update Topic' ),
'add_new_item' => __( 'Add New Topic' ),
'new_item_name' => __( 'New Topic Name' ),
'menu_name' => __( 'Topics' ),
);
// taxonomy register
register_taxonomy('topics',array('post'), array(
'hierarchical' => true,
'labels' => $labels,
'show_ui' => true,
'show_admin_column' => true,
'query_var' => true,
'rewrite' => array( 'slug' => 'topic' ),
));
}