pick an option shopify disable auto select variant on dawn theme

[Hasan112]

disable auto select variant on dawn theme
I tired every thing, 

<option value="{{ variant.id }}" {% if variant == selected_variant %}selected{% endif %}>

someone said remove these lines on product-templete.liquid but can't find this file, 

I tired these lines on product-variant-options.liquid
{% if value.selected %}
checked
{% endif %}

Auto selection option is gone but Add to Cart" functionality do the  function first auto select.


https://help.shopify.com/en/manual/online-store/themes/themes-by-shopify/vintage-themes/customizing-...

same things i wanted but its not available for dawn theme can anyone help me please ?