If the items in the left navigation are not the order desired, it is a simple fix.
Select the main folder that contains all the sub-folders that need a different order.
There are five grey tabs that appear: "Name", "Order", "Last Modified", "Last Modified By" and "Actions". Select "Order".
The folders and pages will be numbered. Number one is what is placed at the very top of the navigation. In most cases, this should be the index page, since it is the home page for the entire folder.
To change the order of the other folders or pages, hover the mouse over the item that needs to move. The mouse will change into an arrow.
Drag the item up or down to change the order.
Check the home page for the folder and make sure the navigation is in the correct order.
When done, publish the folder that contains all of the sub-folders/pages that were just reordered.