Need more documentation of how to reference feeder data

This is a lovely page as far as it goes:

However, it really needs to have examples for each feeder type of how to go about using the feeder data.

I have a file that is an array of json objects, like so:

[{ “propA”: “somevalue”, “propB”: “othervalue”}]

It loads fine, and gives me a List of TrieMaps that looks like this:

“HashMap$HashTrieMap” size = 2

(0) Tuple2
_1 “propA”
_2 “somevalue”
(1) Tuple2
_1 “propB”
_2 “othervalue”

I have a function to populate a Map of form data:

def makeFormData(propA: String, propB: String): Map[String, String] = {
  var formData = Map[String, String](
    "PropA" ->  propA,
    "PropB" -> propB

Then, in my execution, I want to invoke that with data from the feeder:

Seems this works:

val scn = scenario("MySimulation")
    http(session => "mysession")
    .formParamMap(session =>