New Twiddle

components.wizard-slide-body.js

import Ember from 'ember';

export default Ember.Component.extend({
});

components.wizard-slide-header.js

import Ember from 'ember';

export default Ember.Component.extend({
});

components.wizard-slide.js

import Ember from 'ember';

export default Ember.Component.extend({
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

styles.app.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}


.wrapper {
  background: blue;
  padding: 15px;
  margin: 15px 0;
}

.header {
  background: red;
}

.body {
  background: green;
}

.footer {
  background: yellow;
}

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>

{{#wizard-slide as |slide|}}
	{{#slide.header}}
		<p>WIZARD SLIDE HEADER</p>
	{{/slide.header}}
  
  {{#slide.body}}
		<p>WIZARD SLIDE BODY</p>
	{{/slide.body}}

{{/wizard-slide}}

{{#wizard-slide as |slide|}}
	{{#slide.header}}
		<p>Only a header</p>
	{{/slide.header}}

{{/wizard-slide}}


{{#wizard-slide as |slide|}}
  {{#slide.body}}
		<p>Only a Footer</p>
	{{/slide.body}}

{{/wizard-slide}}

{{wizard-slide}}

templates.components.wizard-slide-body.hbs

<div class="body">
  <h1>Body</h1>
  {{yield}}
</div>
  

templates.components.wizard-slide-header.hbs

<div class="header">
	<h1>Header</h1>
  {{yield}}
</div>

templates.components.wizard-slide.hbs

<div class="wrapper">
    {{yield (hash 
    		header=(component 'wizard-slide-header')
        body=(component 'wizard-slide-body')
      )
     }}
  
  <div class="footer">
	  <h1>Footer</h1>
    <p> Some Constant Footer</p>
  </div>
</div>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}