*i don’t have any premium features

I have WooCommerce, Elementor and Phlox Theme

I would like to have the single product page be mobile friendly, I have downloaded the ShopEngine Plugin which effectively allows me to edit the Single Product Page with Elementor, but there is no Add To Cart Button accesible they are all premium, I can access the shortcodes though. Also I can see the functions.php file on my Phlox theme via the cPanel file manager. I would be very thankful for any guidance and help.