Get a Raspberry PI.  I used a model 3B, but others should work.

Get the case from Adafruit and build the Pi into the case (this can be tricky, follow the instructions and comments at Adafruit).  The fit is very tight.  Don't forget to remove the paper backing!

Put the Pi on your home network.  There should be lots of instructions around about how to do this. 

Put the code from GitHub onto your Pi and set it up to run immediately after boot.

That's all there is to it.  You can display anything, including animations with Pygame.