For several years, Linux has used what’s called virtual desktops, and Ubuntu has called its implementation of virtual desktops “workspaces”. Basically, when you boot up and log into your computer, you see your main desktop, but you can then create a number of different virtual desktops that you can switch to, essentially allowing you to have multiple desktops on one computer. You can moving running applications between Workspaces, letting you put, say, LibreOffice Writer documents on one Workspace and spreadsheets on another. (Though a more common use is to put work documents on one and games on another, allowing the user to switch quickly from games to work should the boss walk by.)
By default, the Workspaces feature in Ubuntu 14.04 Trusty Tahr and Ubuntu 14.10 Utopic Unicorn are disabled. Fortunately, it’s quite easy to turn back on.
To enable virtual desktops in Ubuntu, first launch the System Settings application by clicking on its icon in the Launcher, or by going to the Dash, searching for “System Settings”, and clicking on its icon when it appears. After System Settings launches, click on the icon for Appearance, which will be the first icon on the left on the top row.
When the Appearance item opens up, click on the Behavior tab. After the display switches to the Behavior tab, put a check mark on Enable Workspaces check box. This will immediately enable Workspaces, and add a Workspaces icon to the Launcher. You can click on the Workspaces icon on the Launcher to switch between Workspaces, or use the CTRL+ALT+ARROW KEYS to switch between them.