orderId=d023caa6-29dd-41db-a141-c97e789f1397&packagingSplit=[{"pkBinId": "ba11c6f1-90a9-4bf4-ba35-d885d681c920", 

        "Items": [{

            "RowId": "c0c99c53-f8c1-416d-b8b4-32e86c8c42b0",

            "Quantity": 1

        }]},{"pkBinId": "29732799-1d5b-4d0f-b150-bf7ce8f44dc1",

        "Items": [{"RowId": "c0c99c53-f8c1-416d-b8b4-32e86c8c42b0","Quantity": 1}]}]

OrderId and RowId parameters are provided in GetOrdersById call and for pkBinId you can generate random GUID.