The Navigation Tree allows you to drill down through the page hierarchy. You can browse information quickly.
The benefit of browsing through the Navigation Tree is you might stumble upon more information than a normal Search. The Navigation Tree shows all the related pages near the current page, and browsing these pages could show even more helpful information.
Navigation Tree Links Overview

Home Link
This is the root of the Navigation Tree and is always available. Click it to navigate back to the top of the wiki hierarchy.
Current Page
This is the page you are currently on. Looking at the links around this link gives you an idea where you are in the Navigation Tree and the other related pages around it.
Parent Links
Any Link with a down arrow next to it tells you that there are Child Pages under that page.
Docked Links
Any link with a gray background is the parent of all the links below it. Clicking on the Docked Links above it moves you back through the tree.
Sub Links
These links with a blue background are on the same level as your current page. These pages are related to the same Docked Link in the current section.
Child Links
If your Current Page is a Parent, the Child Pages will be listed below. Clicking a Child Link will take you deeper into the hierarchy.
Path (Beginner) - Page Bar