nutrition112

Hello. I am trying to make a custom shopping experience where I have too many variants to fit into one product. There are ~5 different categories each with 10 options each. So we decided to split the products up into different "sub" products. In doing so, I need to create a mini web app that allows the user to choose which items they want to add to the cart culminating into the end where when the user clicks the finish button, the button will trigger an event that will add all 5 products to the cart at once for the user. I however cannot find documentation for the api used by squarespace (api/commerce/shopping-cart/entries) to perform such actions. In essence, I want to be able to programatically access and edit the shopping cart via a code block on a certain page on my website. I know that we cannot add code the checkout page itself, but I just want to be able to edit the cart on other parts of the website. Thanks