single-disorder.php

<?php
/**
 * The template for displaying all single posts
 *
 * @link https://developer.wordpress.org/themes/basics/template-hierarchy/#single-post
 *
 * @package WordPress
 * @subpackage Twenty_Seventeen
 * @since 1.0
 * @version 1.0
 */

get_header();

/* Customization Starts Here */

$therapies = get_field('therapies',get_the_ID());

/* Customization End Here, continued further down */

?>

<div class="wrap">
    <div id="primary" class="content-area">
        <main id="main" class="site-main" role="main">

            <?php
            /* Start the Loop */
            while ( have_posts() ) : the_post();

                get_template_part( 'template-parts/post/content', get_post_format() );

                /* Customization Starts Here */

                if( $therapies ) { ?>
                    <h3>Related Therapies</h3>
                    <ul>
                    <?php foreach( $therapies as $t ): // variable must NOT be called $post (IMPORTANT) ?>
                        <li>
                            <a href="<?php echo get_permalink( $t->ID ); ?>"><?php echo get_the_title( $t->ID ); ?></a>
                            <span>Custom field from $post: <?php the_field('author', $t->ID); ?></span>
                        </li>
                    <?php endforeach; ?>
                    </ul>
                <?php }

                /* Customization End Here */

                // If comments are open or we have at least one comment, load up the comment template.
                if ( comments_open() || get_comments_number() ) :
                    comments_template();
                endif;

                the_post_navigation( array(
                    'prev_text' => '<span class="screen-reader-text">' . __( 'Previous Post', 'twentyseventeen' ) . '</span><span aria-hidden="true" class="nav-subtitle">' . __( 'Previous', 'twentyseventeen' ) . '</span> <span class="nav-title"><span class="nav-title-icon-wrapper">' . twentyseventeen_get_svg( array( 'icon' => 'arrow-left' ) ) . '</span>%title</span>',
                    'next_text' => '<span class="screen-reader-text">' . __( 'Next Post', 'twentyseventeen' ) . '</span><span aria-hidden="true" class="nav-subtitle">' . __( 'Next', 'twentyseventeen' ) . '</span> <span class="nav-title">%title<span class="nav-title-icon-wrapper">' . twentyseventeen_get_svg( array( 'icon' => 'arrow-right' ) ) . '</span></span>',
                ) );

            endwhile; // End of the loop.
            ?>

        </main><!-- #main -->
    </div><!-- #primary -->
    <?php get_sidebar(); ?>
</div><!-- .wrap -->

<?php get_footer();