Hi @jeffelizaga
It means that you need to show the closing and opening </li><li> tag every third entry. It should be something like this:
<?php if(get_field('portfolio_items')) : ?>
<div id="portfolioSlider">
<ul class="slides">
<?php $i = 0; ?>
<li>
<?php while(has_sub_field('portfolio_items')) : $i++; ?>
<div class="col-md-4 wp4">
<div class="overlay-effect effects clearfix">
<div class="img">
<img src="<?php the_sub_field('portfolio_item_image')['url']; ?>" alt="<?php the_sub_field('portfolio_item_image')['alt']; ?>">
<div class="overlay">
<a href="#" class="expand"><i class="fa fa-search"></i><br>View More</a>
<a class="close-overlay hidden">x</a>
</div>
</div>
</div> <!-- END .overlay-effect .effects .clearfix -->
<h2><?php the_sub_field('porfolio_item_title'); ?></h2>
<p><?php the_sub_field('portfolio_item_description'); ?></p>
</div> <!-- END .col-md-4 .wp4 -->
<?php if ($i % 3 == 0){ ?>
</li><li>
<?php } ?>
<?php endwhile; ?>
</li>
</ul> <!-- END .slides -->
</div> <!-- END .portfolioSlider -->
<?php endif; wp_reset_postdata(); ?>
This page should give you more idea about it: http://stackoverflow.com/questions/936242/php-how-do-you-determine-every-nth-iteration-of-a-loop.
Hope this helps.
