how do I get multiple desktops with Mavericks

Bring up Mission Control.

Move your cursor to the upper right side of the screen and a + will appear

Click the + and a new desktop will be created.

Bringing up Mission Control

Applications -> Mission Control -> Keyboard and Mouse shortcuts. This will show you how to bring up Mission Control

Control-Up-Arrow is the default Mission Control hot-key.

<Mac notebooks: Key placement and functions - Apple Support>

If you have a key like this on your Keyboard, this should bring up Mission Control.

Mission Control - Mac Basics

Mission Control Preferences

Mission Control - Shortcuts