There may be other ways to do this, but below is what I tend to do.
Done using the WYSIWYG editor, so choose the <>HTML button (Source code).
First, go further down the page, where you want to jump to. Create a bookmark with the id attribute. For example:
<h2 id="C4">Section 4</h2>
Next, go back up the page and add a link to the bookmark (“Jump to Chapter 4”), from within the same page:
Jump to Section 4
Save your changes and test using Preview.