Linux users have always been used to being able to spread the work load across multiple desktops.
In Raspbian you can right click the desktop and add a new desktop as you want one. But you can't see how many you have and on reboot you are back to only having one desktop again.
First thing to do is to right click the panel and add a Pager.
Once you have done that you will see how many desktops are available and be able to switch between them.
To set the number of desktops permanently:
sudo apt-get install obconf
Once you have installed that, you can find a new option in the Menu under Preferences, called Openbox Configuration Manager.
Click the tab that says 'Desktop' and you will find the option to select the number of desktops you require. Once that is set, rebooting will always bring you back to that number of desktops.