The app widgets will be shown on your Wix store, according to the page type, positions, and placing you set them to be displayed on your funnel settings.
If you selected Thank-you page:
It shows after customers COMPLETE A PURCHASE in your store, depends on the position you set the widgets to be shown in:
See an example:
If you selected the Cart page:
It shows when a customer visits your cart page, after adding products to the cart
If you selected the Checkout page:
It shows when a customer visits your store's checkout page (After clicking on CHECKOUT on the cart page)