Generally digital signage requires one media player per display.  Each media player can play a different playlist if you would like, or they can all be assigned the same playlist.  

If you would like to use a single media player to mirror the same content to two or more screens at the same time, you can purchase an HDMI splitter (available via Amazon and other retailers) that has a single input and multiple outputs. Note that in this scenario you will need to run one HDMI cable from your media player to the splitter, then one HDMI cable from the splitter to each one of your screens, so you may end up with a lot of cables in your workspace. 

If you wish to set up a video wall where one media player stretches your content across multiple, adjacent screens (essentially a multi-screen billboard) then please see this article instead. Please contact us with any questions; we know that multi-screen setups can be confusing!