The output settings control the monitor and (text) appearance. There will be an entry for each available output.
Select the right arrow to configure each output.
The Personal and Express editions support a single output.
The Standard editions support two outputs
The Premium edition supports six outputs
At first you might think that you'll never use six outputs if your system does not have six physical outputs attached. It's worth noting that an output is not restricted to the "full screen" of a physical monitor. This is where Custom Monitors come in: they are defined to be any area on the Windows desktop, which might be a small window area (eg. picture-in-picture) or a large area spanning more than one physical displays.