Product pages - Allow pre-orders for products

Store Design
14

I am using Warehouse Theme. I cannot find these codes,

addToCart: {{ 'products.product.add_to_cart' | t | json }}, 

<span data-add-to-cart-text>
  {% unless current_variant.available %}
  {{ 'products.product.sold_out' | t }}
  {% else %}
  {{ 'products.product.add_to_cart' | t }}
  {% endunless %}
</span> 

Hope you can help me. Thanks.