<header id="header">

  <div class="landmark-content header-content">
    <h1 class="main-title"><a href="{{ site.baseurl }}/">{{ site.title }}</a></h1>
    <nav>
      <ul id="main-nav">
        <li><a href="{% link index.html %}">Home</a></li>
        <li><a href="{% link about.md %}">About</a></li>
      </ul>
    </nav>
  </div>

</header>

<header id="header">

  <div class="landmark-content header-content">
    <h1 class="main-title"><a href="{{ site.baseurl }}/">{{ site.title }}</a></h1>
    <nav>
      <ul id="main-nav">
        <li><a href="{% link index.html %}">Home</a></li>
        <li><a href="{% link tags.md %}">Tags</a></li>
        <li><a href="{% link about.md %}">About</a></li>
      </ul>
    </nav>
  </div>

</header>

Add link to tags page in navigation
Add link to tags page in navigation
