This is code example of how to add "Related video" for themes "Summer Triangle", "Polaris", "Vela", "Phoenix", "Chameleon"

_related_video.liquid

// You have to create boolean custom field and get the id number. In this example I will use custom field with id 1425, 
// so condition will looks like this if program.custom_fields.custom_field_1425.value

// You have to create a category which will be displayed on program page and get this category id. I will use '10361' id,
// so assignment will looks like this assign featured_category = '10361' | get_category

// All this code you have to include to liquid snippet. Just create a file "_related_video.liquid" and then
// call it in program.liquid tamplate like this: {% include 'related_video' %} in the bottom of the page

{% comment %}
  Snippet code for Related video section
{% endcomment %}
{% if program.custom_fields.custom_field_1425.value %}
  {% assign featured_category = '10361' | get_category %}
  <div class="featured_category">
    <div class="container">
      <hgroup class="featured_category--headers">
        <h2 class="featured_category--title">{{featured_category.title}}</h2>
      </hgroup>
      <div class="justify-content-center">
        <div class="row">
          {% for program in featured_category.programs_preview | limit: 12 %}
            {% include 'card' %}
          {% endfor %}
        </div>
      </div>
    </div>
  </div>
{% endif %}