Redirect to "Add Ons" page after clicking "Add to Cart"

Site URL: https://www.ballybrookfarm.com/glamp-dates-calendar/available-glamping-getaway

Hello! After digging through the forum, the only solution I can find is the plugin from sqspthemes (https://www.sqspthemes.com/blog/how-to-add-an-upsell-page-to-your-squarespace-store) which does not seem to be working for a "product block".  At least the plugin isnt working when I am attempting it. I have tried inserting the plugin in the "additional info" of the product and as well in the header section code injection. No luck with each.

I am attempting to redirect the customer to an "addons" page as soon as they add a specific product to the cart.

Page containing the product block I want them to add to cart: https://www.ballybrookfarm.com/glamp-dates-calendar/available-glamping-getaway

Addons page I want customer to redirected to once first product is added to cart:  https://www.ballybrookfarm.com/add-ons

Thank you for any help from anyone!!

Kate