The images below were used to make the navbar. When you make a navbar, each tab is put into a table. Make sure the bar underneath is outside of the table, otherwise it will mis-align.

To put a navbar (you can only have one per page) into your document go to the insert menu and choose

Insert => Interactive Images => Navigation Bar.

Index

This is a navigation bar.

Notice the four states to each tab.

The images to make this rollover can be found below.
There are thirteen in all - four for each tab, and one for the bar underneath.