Quantity selection box code for Wix Stores API as dynamic page

Has anyone worked out the code required to have a quantity selection box function properly on a dynamic product item page. I am starting to build my own product page running Wix stores API and it’s going to take a long time. I need to know the code required to have a functioning quantity selection box that adds the required amount to the cart and deducts the exact quantity for the store database…

Any help would be well received. Thanks

I need this as well

Have you figured this out ?