Regarding populating a squarespace cart from url

I need help in integrating a buy button from site abc to a SquareSpace web store.

The integration must enable a url with ref parameter abc and with product/variant information, quantity, and (optional) discount code to populate the store cart. The in-app  buy button will open this url in a nested browser and populate the squarespace cart, and then redirect to the abc app after purchase.

I have setup a demo squarespace account with the business plan. I have added few products in my store. But confused on how to proceed further for setting up the url for cart generation in squarespace. 

Any suggestion on how to achieve this would be of great help.

1 hour ago, Abhilash_K said:

I need help in integrating a buy button from site abc to a SquareSpace web store.

The integration must enable a url with ref parameter abc and with product/variant information, quantity, and (optional) discount code to populate the store cart. The in-app  buy button will open this url in a nested browser and populate the squarespace cart, and then redirect to the abc app after purchase.

I have setup a demo squarespace account with the business plan. I have added few products in my store. But confused on how to proceed further for setting up the url for cart generation in squarespace. 

Any suggestion on how to achieve this would be of great help.

Can you share your the url of squaresoace site and the target website with the button that needs integrated to squarespace?