Nothing is required just depends on how you want to set it up.
If you want to install the app and run it from a home computer follow the instructions on the Github page.
If you just want to start using the app and don’t have a server to run the app you can use the hosted version on Ray’s website available here: http://rayshobby.net/apps/sprinklers/. The only thing to keep in mind with this option is you need to forward the port used to the outside. Just Google port forwarding if your unfamiliar with this terminology. The OpenSprinkler natively uses port 80 but your welcome to change it.
If you need further help from here feel free to ask!