Common Video Output Device represent screens arranged on the OS desktop, but can also be output texture or network stream.
To configure a video output, go inside preferences (F11) and select the video output here.
Now apply the changes and eventually reopen preferences in order to have access to the full parameters of the output :
It is here that you will any kind of output, such as
How to configure Spout Input and Spout Output
You can also directly choose here on which screen you want your output to be :
You can also check
Configure the Video Output
Display your content on output monitors
for further details of the process.
In order to be working video outputs need to be enabled with the
Enable/Disable Video Outputs
Use the [Ctrl]+[Shift]+[Alt]+[W] shortcut in order to disable video outputs, in case you did wrongly configure them.
Whether you see this problem in your devices
or this one in your video outputs;
it means that you have to add the requested number of
Remove watermark on inputs and outputs channels
to your device.