In DITA XML, you can create links to navigation elements and tables of contents (TOCs) using specific elements and attributes. These links are essential for enhancing user navigation within your documentation. Here’s the syntax and an example of how to create these links:

1. Navigation Elements: To link to navigation elements like menus, you typically use HTML and CSS to structure your navigation, and then you can create links to the corresponding sections within your DITA topics. Here’s an example:

<div class="menu">
  <ul>
    <li><a href="#section-1">Section 1</a></li>
    <li><a href="#section-2">Section 2</a></li>
  </ul>
</div>

<section id="section-1">
  <title>Section 1</title>
  <p>Content of Section 1.</p>
</section>

2. Table of Contents (TOC): To link to a hierarchical TOC, you can use the <tocentry> element within a <toc> structure. Each <tocentry> can include a <topicref> element with a href attribute pointing to the topic you want to include in the TOC. Here’s an example:

<toc>
  <title>Table of Contents</title>
  <tocentry>
    <topicref href="#section-1"/>
  </tocentry>
  <tocentry>
    <topicref href="#section-2"/>
  </tocentry>
</toc>

By using the appropriate syntax for links, you can create effective navigation elements and TOCs in DITA XML that help users easily navigate your documentation.