How to change the local payload when invoking a lambda in cloud9 IDE?

Question

I'm developing in AWS Cloud9, and have a basic "Hello, World" API set up using Lambda.

Now I would like to iterate so that the API can accept parameters. Cloud9 used to have a convenient UI for modifying the payload when running "local" (in the IDE, without deploy). But I can't find where this has been moved, and the documentation still references the previous UI.

To test this, I've included a simple print(event) in my Lambda, and started modifying various components. So far I only print an empty dict ({}). I suspect it's in the launch.json but so far everything I've modified has not been picked up. Showing below

{
    "configurations": [
        {
            "type": "aws-sam",
            "request": "direct-invoke",
            "name": "API token-to-geojson:HelloWorldFunction (python3.9)",
            "invokeTarget": {
                "target": "api",
                "templatePath": "token-to-geojson/template.yaml",
                "logicalId": "HelloWorldFunction"
            },
            "api": {
                "path": "/hello",
                "httpMethod": "get",
                "payload": {
                    "json": {}
                }
            },
            "lambda": {
                "runtime": "python3.9"
            }
        },
        {
            "type": "aws-sam",
            "request": "direct-invoke",
            "name": "token-to-geojson:HelloWorldFunction (python3.9)",
            "invokeTarget": {
                "target": "template",
                "templatePath": "token-to-geojson/template.yaml",
                "logicalId": "HelloWorldFunction"
            },
            "lambda": {
                "payload": {
                    "ticky": "tacky"
                },
                "environmentVariables": {},
                "runtime": "python3.9"
            }
        }
    ]
}