Thinking of going premium, if….

Hi.
I am going to buy premium to unlock certain features but I need help with this important thing first to make sure it all works.

Currently on my website you can only add products to quote when you are on the product page itself. On my website however, I have “Latest products” and product categories where an “Add to cart” button would appear when you move the cursor over a product. See image example here: http://postimg.org/image/jva2rex2n/
I am now trying to change this button’s function to instead of adding the product to cart, it gets added to quote.
In content-product.php I see the following:

$link    = apply_filters( 'add_to_cart_url', esc_url( $product->add_to_cart_url ) );
            $label    = apply_filters( 'add_to_cart_text', __('ADD TO CART', THEMENAME) );
         break;
      }

      if ( $product->product_type != 'external') {
         $zlink = '<a href="'. $link .'" rel="nofollow">id.'" class="add_to_cart_button product_type_'.$product->product_type.'">'. $label.'</a>';
      }
      else {
         $zlink = '';
      }
   }

What shall I replace in that code to make the product go into quote list? I tried a lot of things but it isnt working.
Hope you can help.
Thanks

https://wordpress.org/plugins/yith-woocommerce-request-a-quote/