Comment créer un système Upsells Panier sur Shopify

<style>
  .dgCartUpsell { text-align:center; margin:25px auto; max-width:1170px; }
  .dgCartUpsellCont { margin:0 auto; }
  .dgCartUpsellInner {  display:inline-flex; margin:0 auto; border:1px solid #f0f0f0; }
  .dgCartUpsellForm {  max-width:300px; padding:10px 15px; margin:10px; }
  .dgCartUpsellForm * { display:block; clear:both; width:100%; margin-bottom:15px; }
  .dgCartUpsell .dci-title { font-size: 16px; line-height: 21px; min-height: 45px; }
  .dgCartUpsellQty { display:none !important; }
  .dgCartUpsell input[type=number] { float:none; display:block; }
  .dgCartUpsell .btn-primary, .dgCartUpsell .btn-primary:hover { }
</style>

{% assign upsellCollection = "upsells" %}
{% assign upsellLimit = "4" -%}
{% assign upsellTitle = "Et si vous craquiez aussi pour... ?" %}
{% assign upsellAtc = "Ajouter au panier" %}


<div class="dgCartUpsell">

  <h2>{{ upsellTitle }}</h2>

  <div class="dgCartUpsellCont">
    {% for collection in collections  %}
    {% if collection.handle == upsellCollection %}

    {% for product in collection.products limit:upsellLimit %}

    <div class="dgCartUpsellInner">

      <form action="/cart/add" method="post" class="dgCartUpsellForm">
        <img class="dci-image" src="{{ product | img_url: '600x600', scale: 2 }}" alt="{{ product.title | escape }}" >
        <strong class="dci-title">{{ product.title }}</strong> 

        <select name="id" class="dci-product-variants" >
          {% for variant in product.variants %}
          {% if variant.available %}    
          <option {% if variant == product.selected_or_first_available_variant %} selected="selected" {% endif %} data-sku="{{ variant.sku }}" value="{{ variant.id }}">
            {% if variant.title != "Default Title" %}{{ variant.title }} - {% endif %}
            {{ variant.price | money_with_currency }}            
          </option>
          {% else %}
          <option disabled="disabled">
            {{ variant.title }} - {{ 'products.product.sold_out' | t }}
          </option>
          {% endif %}
          {% endfor %}
        </select> 
        <div class="dgCartUpsellQty">
          <label for="quantity-{{forloop.index}}">Quantité</label>
          <input type="number" id="quantity-{{forloop.index}}" name="quantity-{{forloop.index}}" value="1" min="1" class="quantity-selector"> 
        </div>
        <button type="submit" name="add" class="btn btn-primary">{{ upsellAtc }}</button>
      </form>
    </div>
    {% endfor %}
    {% endif %}
    {% endfor %}
  </div>
</div>

{% include 'dg-cart-upsells' %}