Custom Panel Field tutorial

Hi folks. I’m new to Kirby 5 (I have a couple of sites running Kirby 3) and I’m trying to create a custom plugin by following the tutorial here: Custom Panel field | Kirby CMS

I’ve followed the first few steps, but when I add the field to a blueprint it won’t show up in the editor. I’m pretty sure it’s not a configuration error as I don’t see the red warning box (that says ‘x field is not defined’), but I don’t see the ‘Hello’ message in the editor.

Per the tutorial, here’s my folder structure:

The content of package.json:

{
  "scripts": {
    "dev": "npx -y kirbyup src/index.js --watch",
    "build": "npx -y kirbyup src/index.js"
  }
}

The content of index.php:

<?php

Kirby::plugin('pluginAuthor/doi', [
    'fields' => [
        'doi' => [
          // here we could define the backend logic for our field if needed
        ]
    ]
]);

The content of src/index.js:

panel.plugin('pluginAuthor/doi', {
  fields: {
    doi: {
      template: "<p>Hello</p>"
    }
  }
});

And the content of my blueprint (comic.yml):

title: Comic
icon: 🖼

status:
  draft: true
  listed: true

fields:
  doi:
    type: doi
    label: DOI name

I’ve run the build script in the plugin folder, and it’s generated an index.js in the plugin root as expected:

(function() {
  "use strict";
  panel.plugin("pluginAuthor/doi", {
    fields: {
      doi: {
        template: "<p>Hello</p>"
      }
    }
  });
})();

But this is what I see when creating a new comic using the blueprint:

I’d expect to see ‘Hello’ there, per the tutorial.

Any ideas where I could be going wrong?

Solved - after following the tutorial to the end, the input’s now showing. Does the first step (inlined template) no longer work with Kirby’s plugin architecture?