DariushGreat

I found it 😀 Yeeeeeeeeaaaahhhhhh :))))
This is final code that worked! I explained each level 😉

/* for get author ID use these */
$curauth = (isset($_GET['author_name'])) ? get_user_by('slug', $author_name) : get_userdata(intval($author));
$author_id = get_the_author_meta('ID');

/* First condition */
if( get_the_author_meta('management_certi', $author_id, true)) {
	/* get file ID */
	$id = get_user_meta( $author_id, 'management_certi');

	if($id) {
		/* Array Loop! */
		foreach($id as $attachments) {
			/* get file URL */
			$url = wp_get_attachment_url( $attachments ); ?>
			<a href="<?php echo $url; ?>" data-lightbox="image-1" data-title=""><img src="<?php echo $url; ?>" class="thumbnail" width="36" height="36" /></a>
		<?php
		}
	}
} else { echo '--'; }

Help me please 🙁 :'(