Redirect page to first post in custom post type

This is assuming that your page ‘Artists’ has an ID of 10, so change that as necessary.

You can also amend the $args array as you wish to better suit your needs, if required. Here is the Codex for WP_Query, which shows that parameters that you can use.

Finally, this needs to go right at the top of your page (before any output), otherwise you’ll get an error about header information having already been output.

if(is_page(10)) :

    $args = array(
        'posts_per_page' => 1,
        'post_type' => 'artists'
    );

    /** Get the posts that match and grab the URL of the first post */
    $posts = get_posts($args);
    $redirect_url = get_permalink($posts[0]->ID);

    /** Redirect to the specified URL */
    wp_redirect($redirect_url);
    exit;

endif;