Theme Integration

Per the instructions:

"2. Edit product-adder.php
When you complete step 1, just open newly created file (product-adder.php) and find the loop (see The_Loop). The loop usually starts with a:

<?php if ( have_posts() ) : ?> or <?php while ( have_posts() ) : the_post(); ?>

And ends with:

<?php endif; ?> or <?php endwhile; ?>

This varies between themes. Once you have found it, delete it. In its place put:

<?php content_product_adder(); ?>"

I get an error in my “loop” when I try to add in the code. what do I do?

This is my loop:

<?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
          <?php the_content(); ?>
          <hr />
          <?php endwhile; else: ?>
          <p>
            <?php _e('Sorry, no posts matched your criteria.'); ?>
          </p>
          <?php endif; ?>

which do I delete? If i replace the <?php endwhile; else: ?> I have an error

IF i replace the <?php endif; ?> I get an error.

https://ww.wp.xz.cn/plugins/ecommerce-product-catalog/