The navigator displays a list of symbols, identifiers, and other notable code sections that it has found in the current document. In HTML mode, this includes things like <div> IDs and header tags. In PHP mode, it includes function definitions. Click on one of these symbols to jump to its location in the editor.
By default, the navigator lists symbols in the order they appear in the document. You can re-sort the list by name or kind by clicking on the sort button at the bottom of the Navigator sidebar.
To search for a symbol by name, click in the search box at the bottom of the Navigator sidebar then start typing the name.