// Add Meta Box
function entzhood_add_download_metabox() {
    add_meta_box(
        'entzhood_download_links',
        'Download Links',
        'entzhood_download_metabox_callback',
        'post',
        'normal',
        'high'
    );
}
add_action('add_meta_boxes', 'entzhood_add_download_metabox');

// 2. Meta Box Fields
function entzhood_download_metabox_callback($post) {
    $movie_link = get_post_meta($post->ID, '_entzhood_movie_link', true);
    $subtitle_link = get_post_meta($post->ID, '_entzhood_subtitle_link', true);
    $series_links = get_post_meta($post->ID, '_entzhood_series_links', true);

    wp_nonce_field('entzhood_save_download_links', 'entzhood_download_nonce');
    ?>
    <p>
        <label for="entzhood_movie_link">Movie Download Link:</label><br>
        <input type="text" id="entzhood_movie_link" name="entzhood_movie_link" value="" size="50" />
    </p>
    <p>
        <label for="entzhood_subtitle_link">Subtitle Download Link:</label><br>
        <input type="text" id="entzhood_subtitle_link" name="entzhood_subtitle_link" value="" size="50" />
    </p>
    <p>
        <label for="entzhood_series_links">Series Download Links (separate by commas):</label><br>
        <textarea id="entzhood_series_links" name="entzhood_series_links" rows="4" cols="50"></textarea>
    </p>