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You will need to use these combinations of block. The offerings block will give you all available items for purchase and stored within the offerings object. All items will be put into a list under “availablePackages”. From there, you need to identify the index of the list of products you want.
Upon a successful purchase, the green purchase block will contain information similar to the ones in “Customer Info”. It will contain information on all the items purchased. If you want to access the quantity of the product purchased, it will depend on what kind of product it is. I would look into the example JSON for the part of the object that would be most useful for you. I would default to allPurchasedProductldentifiers or allPurchaseDates.