If you like to install a video wall or in case you will display the same content on multiple screens nearby you can use one player with one license.
In the case you are willing to display the same content (multiple copies of the content), you are going to need a HDMI splitter which imparts the signal to all screens.
If you want to do a videowall with just von player (content beeing spread across all the screensto) , your screens need to support DVI or DP daisy chain like most of the videowall displays do. Than, you can plug in the player in the first screen and make a loop through to the other screens. Now you just need to set the screen settings on videowall and you are done.