In your account, you have access to 7 different applications: Calendars, Files, Photos, Bookmarks, Discussions, To Dos, and Addresses. Each of these applications is listed in your Navigator on the left-hand side of the screen. If you do not see one of these applications in your Navigator you may need to turn it on in the Manage Applications dialog.
The applications are listed in a default order in your Navigator, but you also have the option of rearranging the applications so that they're in the order of your choosing. To change the order of your applications follow the steps in the image below: