Ubuntu 13.04 Raring comes with workspaces disabled by default. So you’re unable to switch between workspaces via hot-keys or shortcut icon on Unity Launcher.
To enable this feature, search and open Appearance in Unity Dash.
Then you can easily switch on or off the wordspaces as well as the shortcut keys at Behaviour tab.
After enabled this feature, use Ctrl+Alt+ Up (Down, Left, Right) key combination to switch between wordspaces. Or click the “Workspace Switcher” icon on Unity Launcher to view workspaces.