After the import step go to the response mapping and create a mapping for the _json field as the following

The HTTP response looks like the following
{
  "data": {
    "purchaseOrders": {
      "register": {
        "eventDate": "2022-06-03 06:21:43.564400 -04:00",
        "pickupDate": "2022-06-03 06:21:43.000000 -04:00",
        "consolidatedShippingLabel": {
          "url": "https://sandbox.api.wayfair.com/v1/shipping_label/DE405443810"
        },
        "shippingLabelInfo": [
          {
            "trackingNumber": "5541612245",
            "carrier": ""
          }
        ],
        "purchaseOrder": {
          "poNumber": "DE405443810",
          "shippingInfo": {
            "carrierCode": "XDPE"
          }
        }
      }
    }
  }
}Then in the field mapping add the path to this value in HTTP response and map it with the field in which we need to add this data
