Reply To: setting up produt pages

I’m sorry but I haven’t solved the problem, the only way to have the ability to manage the quantity of the product is to copy the product from a demo, specifically I copy the item “Variable product example”, but if I change the settings from variable product to simple product, I no longer have the possibility to manage the quantity, I thought that the problem may be generated by the YITH plugin.
Finally I don’t know how to add the Content in the Description area.

Thank you