Classic Controller

controllers.alpha\.js

import Controller from '@ember/controller';

export default Controller.extend({
  init() {
    this._super(...arguments);
    console.log('INIT: Alpha Controller');
  }
});

controllers.application\.js

import Controller from '@ember/controller';

export default class ApplicationController extends Controller {
  appName = 'Ember Twiddle';
}

controllers.beta\.js

import Controller from '@ember/controller';

export default Controller.extend({
  init() {
    this._super(...arguments);
    console.log('INIT: Beta Controller');
  }
});

controllers.delta\.js

import Controller from '@ember/controller';

export default Controller.extend({
  init() {
    this._super(...arguments);
    console.log('INIT: Delta Controller');
  }
});

controllers.gamma\.js

import Controller from '@ember/controller';

export default Controller.extend({
  init() {
    this._super(...arguments);
    console.log('INIT: Gamma Controller');
  }
});

router\.js

import EmberRouter from '@ember/routing/router';
import config from './config/environment';

const Router = EmberRouter.extend({
  location: 'none',
  rootURL: config.rootURL
});

Router.map(function() {
  this.route('alpha');
  this.route('beta');
  this.route('gamma');
  this.route('delta');
});

export default Router;

routes.alpha\.js

import Route from '@ember/routing/route';

export default Route.extend({
});

routes.beta\.js

import Route from '@ember/routing/route';

export default Route.extend({
});

routes.delta\.js

import Route from '@ember/routing/route';

export default Route.extend({
});

routes.omega\.js

import Route from '@ember/routing/route';

export default Route.extend({
});

templates.alpha\.hbs

<h2>Alpha</h2>

templates.application\.hbs

<menu>
  <ul>
    <li>
      <LinkTo @route="index">Home</LinkTo>
    </li>
    <li>
      <LinkTo @route="alpha">Alpha</LinkTo>
    </li>
    <li>
      <LinkTo @route="beta">Beta</LinkTo>
    </li>
    <li>
      <LinkTo @route="gamma">Gamma</LinkTo>
    </li>
    <li>
      <LinkTo @route="delta">Delta</LinkTo>
    </li>
  </ul>
</menu>
{{outlet}}
<br>
<br>

templates.beta\.hbs

<h2>Beta</h2>

templates.delta\.hbs

<h2>Delta</h2>

templates.gamma\.hbs

<h2>Gamma</h2>

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}