The new mission control app is probably one of the most prevalent changes to the usability of OS X. But many users are startled by the apparent removal of spaces. Never fear! Most of the functionality of spaces exists in mission control.
Tip 1: Spaces are now Desktops.
Desktops are the equivalent of spaces in Lion. In mission control, the top row displays the current desktops. To add a new desktop, hover the cursor to the far left of the row and you’l see a ‘+’ icon appear. Click this icon and a new desktop will be created.
Tip 2: Desktop shortcuts.
Switching desktops is similar to switching spaces in 10.6. Simply type ctrl? or ctrl? to switch to the next / previous desktop. Doing the same from mission control will advance to that desktop within mission control. To move a window to a new desktop, drag the window while in mission control to another desktop in the desktop row above.
Tip 3: Lock / Pin an application to a specific desktop.
From the new desktop, right click the dock icon for the application, select Options->Assign To. From here you can select ‘This Desktop’ to pin the application to the current desktop.
Lastly, how do you name the desktops?
New desktops will be named Desktop 1, Desktop 2, etc. Full Screen windows appear as their own desktop and are named by the application (Safari, iTunes, etc). At this point there is no way to change the name of a desktop.