would be nice if you knew what they had wired up already, some places are wired already to just plug in but if not you need a network switch (if they don't have a DJM-2000 as the mixer) and 3 cat5/6 cables, 2 go from the players to the switch and the 3rd goes from the laptop to the switch so they are all on the same network
if on PC you will need to allow RB things running to be "allowed" if they pop up. Make sure you disable wireless altogether also so RB is not looking through some wireless network you may be on like cable vision, verizon, etc....