Would like to show "quantity available" on product pages

Hi, I'm looking to create a squarespace site for my mom who sells hand-dyed yarn. Her current site allows her to show how many hanks of yarn are available on each yarn product page. When a customer purchases less than the number of hanks available, the product listing updates and shows the new quantity available. Can this be done with Squarespace? Possibly with code? I am not great with code, but if someone told me what code to use and where to put it, I could probably handle that. Thank you in advance!