Hello,
I’m completely confused. You ask about WooCommerce sorting options and we told you that we don’t have any settings to change this, we sent you video tutorial how you could implement this. This is WC plugin default option. If you need help or detailed explanation for WC plugin options you need to contact WC plugin support. I’m sorry, but we provide support only for our theme settings and options. Feel free to ask us any questions about them but if you need help with WC plugin options or settings, please, contact WC plugin support because these questions are outside the scope of our support.
If you want to make any change on your site or want to implement the new functionality you need to use child theme. What child theme is and how it works you can read here.
If you watched video tutorial you see that there was used custom-function.php file because that tutorial was created for theme from TemplateMonster. In your case, you need to use child theme functions.php to add the code https://www.templatemonster.com/help/woocommerce-how-to-remove-some-options-from-the-sort-by-list.html
If you have any other questions about this customization either contact WC plugin support or customization team because our base support does not cover such questions.
Regards