Displaying data from a REST call returning data in parent child structure

Summary

Displaying data from a REST call returning data in parent child structure

Content

Hello Experts,

I am just starting on VBCS, building a page which shows data in a table. I am fetching the data via a REST call which gets data in a Header and child structure

for ex. "items":    [
{
"ShipmentHeaderId": 000,
"PaymentTermsId": null,
"PaymentTerms": null,
"CurrencyCode": null,
"HeaderInterfaceId": 000,
  "shipmentLines": [         {
    "ShipmentLineId": 000,
    "ShipmentHeaderId": 00,
    "LineNumber": 1
                      }
                   ]
}
]

My requirement is to show this data in a normalized way i.e get couple of columns from header and rest from child and show them in table. If I directly call REST and map it with table data it works but when I map an ADP variable with table data and populate  that variable(on button click) with REST result it doesn't work.