Using an Orchestrator to process or generate a JSON request, how do you read or produce a JSON with

Using an Orchestrator to process or generate a JSON request, how do you read or produce a JSON with a nested list, example a list of items and a list of costs and types for each item.

Many outside companies supply nested arrays on the supplied JSON, or want them from a provider service.  I can't see how to do this in Orchestrater.