Take at the look at the documentation again, it has some examples. Get Rid of the $ and the dot.
program Project1;
uses System.SysUtils, System.JSON;
begin
var myjson:=TJSONObject.ParseJSONValue('{"name": "Chris","value": 10000}');
var myval:=myjson.FindValue('name');
Assert(myVal.Value() = 'Chris');
end.
Or here, with arrays:
program Project1;
uses System.SysUtils, System.JSON;
const
json =
'{'+
' "name": "Chris",'+
' "pets": ['+
' {'+
' "name": "Rufus",'+
' "type": "dog",'+
' "age": 10'+
' },'+
' {'+
' "name": "Wraabargl",'+
' "type": "Dinosaur",'+
' "age": 113'+
' }'+
' ]'+
'}';
begin
var myjson:=TJSONObject.ParseJSONValue(json);
var myval:=myjson.FindValue('pets[1].type');
Assert(myVal.Value() = 'Dinosaur');
readln;
end.