The Navigation is a set of buttons that links to your pages. To add a navigation go to Insert  ribbon and click on Navigation 
This is mostly used as a template element. The reason is simple, the purpose of the navigation bar is to allow your website visitors to navigate through all the pages in your website. By placing this bar into your template, it will automatically appear on every page in your website. If you were to insert the navigation bar into an individual page, it will only be visible on the single page you placed it onto - it would suddenly disappear as soon as someone clicks on one of the menu items in the navigation bar to go to a new page.
You can add navigation to individual pages, however it's only recomended when you have a separate group of subpages that you don't want to be displayed in the main navigation.
To do that just select the level of navigation bar from the settings.
The Edit Level button works like this:
Level 1 will be your main pages.
Level 2 will be your subpages.
Level 3 will be your sub-subpage.. and so on.
The level of navigation is global, so if you set level 2 you'll get all the pages from level 2 in your site.
The editing options are:
Direction - You can make your navigation bar Horizontal  or Vertical  .
Button Type - The button types are Rectangular , Rounded Corners , Tabs Upwards , Tabs Downwards  or Text Only . With the exception of Text only you can change the value of Rounding  from 0% to 100% for all others types.
Button Shading - There are 6 types of Button Shading.
Button Alignment - You can edit the width of the button, Variable , Fixed  or Stretch to fit . You can also change the Alignment of the buttons to the Left , Right  or Centered .
Padding - This has two options: one for Horizontal navigation wich has the following options, Horizontal Button Padding , Outside Padding  and Padding Between Buttons . And in the Vertical navigation you have Horizotal Button Padding , Vertical Button Padding , Outside Padding  and Padding Between Buttons .
Text Style - Here you can change the font, size , make it bold, italic or underlined , and change the alignment  of the text inside the navigation.
Colors - This lets you edid the Background  of your navigation, the Button Colors  and the Text color .