Wrote up a quick example of creating structured component templates in 1.10:
Instantiate component like this:
{{#my-comp as |section|}}
{{#if section.isHeader}}
My header
{{else if section.isBody}}
My body
{{else if section.isFooter}}
My footer
{{/if}}
{{/my-comp}}
Results in
<div>
<header>My header</header>
<div class="body">My body</div>
<footer>My footer</footer>
</div>