Add sub navigation

You can add the Sub navigation by default just adding the nav be-sub-navigation between the be-top-header and be-content wrapper element, like this:

<html lang="en">
  <body>
    <div class="be-wrapper be-nosidebar-left">
      <nav class="navbar navbar-default navbar-fixed-top be-top-header">
        <!-- Top bar -->
      </nav>

      <nav class="navbar navbar-default be-sub-navigation">
        <!-- Sub navigation -->
      </nav>

      <div class="be-content">
        <!-- Main content -->
      </div>
      <div class="be-right-sidebar">
        <!-- Right sidebar -->
      </div>
    </div> 
  </body>
</html>