Menu from Front Matter (+ multi-level)

Thanks for the explanation, but it is still a bit confusing.
I have changed front matter to this state:

menu:
  templates:
    title: "templates"
  docs:
    title: "Documentation"
    parent: "templates"

Now when i do {{ range .Site.Menus.docs }} i can get the Docs menu item as a child, but the parent field is empty:

<ul class="top-level">              
    <li>
        <a href="#"></a>
    </li>
    <ul class="sub-menu">            
        <li>
        <a href="/blog/dota2-guide/">Documentation</a>
        </li>            
    </ul>   
</ul>

And if i do {{ range .Site.Menus.templates }} i get only Templates menu item as parent, with no children