During automatic installation, the app typically searches for files like product.liquid or product-template.liquid in your theme.
However, since each Shopify theme has a unique structure and logic, the product page may use a different template file — causing the options not to display automatically.
Solution:
To resolve this, identify the correct product template used in your theme and manually insert the following code snippet into it:
<div id="hulkapps_custom_options_{{ product.id }}"></div>