How to show subtitle

The subtitles work well on native posts however am using a plugin that shows the posts and its not showing the subtiles. For the title the author has used this code `<!– Blog Title –>
<div class=”otw_blog_manager-blog-title-wrapper otw_blog_manager-format-image”>
<?php
$titleLink = $this->getLink($post, ‘title’);
if( !empty($titleLink) ) :
?>
<h3 class=”otw_blog_manager-blog-title”><a href=”<?php echo $titleLink;?>”><?php echo $post->post_title;?></a></h3>
<?php else: ?>
<h3 class=”otw_blog_manager-blog-title”><?php echo $post->post_title;?></h3>
<?php endif; ?>
</div>
<!– End Blog Title –>`

How canI call the subtiles below the title? Thnaks

https://wordpress.org/plugins/subtitles/