Places screen – Backend screen options

Hi Guust,

Please give me some details of how to do this by myself.

Should I add this kind of code to functions.php?

add_filter('manage_posts_columns', 'my_columns');
function my_columns($columns) {
    $columns['geodir_Visibility'] = 'Visibility';
    return $columns;
}

add_action('manage_posts_custom_column',  'my_show_columns');
function my_show_columns($name) {
    global $post;
    switch ($name) {
        case 'geodir_Visibility':
            $visibility = get_post_meta($post->ID, 'geodir_Visibility', true);
            echo $visibility;
    }
}

Or must I interfere to plugins code?

Thanks