Unable to get appId through installing Wix Stores app

Question:
How do I get access to my appId variable so that I can use it in ‘wix-ecom-backend’ API to add items to cart

Product:
Wix Editor and Wix Stores app

What are you trying to achieve:
My end goal is to be able to click on a button on a page, and be able to add an item to the cart and be redirected to the cart page. To do this I’m using the ‘wix-ecom-backend’ API CurrentCart.addtoCurrentCart function to add an item to the cart but in the options, the appId is needed.
And to get the appId I’m told to install and configure the Wix Stores app.
But after following the Wix Store setup, I’m getting a “getConfig was not implemented” error in the Wix Logs. And no mention of the appId in the logs.

How should I go about this ?