1) Using a browser (Chrome, if possible), go to this case-sensitive URL: http://WO-SIGNAGE-CMS/ContentManager
Login with these credentials:
http://WO-SIGNAGE-CMS/Content Manager is an internal web site that may only be accessible from specific locations.
2) Click on Players
Click on the name of the player you are interested in to access its properties.
Select the drop down for "Channel @ Display 1" and select "No Content". Save changes by clicking on Save. It will take up to 2 minutes for the changes to show on the screen.
To revert back, simply follow the same instructions as above but select the prior setting for "Channel @ Display 1".