Once a Arduino DAQ is purchased, the IDE (integrated development environment) needs to be downloaded ( available from https://www.arduino.cc/) so that you can communicate with it easily from your PC.
As the Arduino will be communicating with Node-Red, programming and control logic will not be done on the Arduino board itself, as many other projects do, but rather on the PC the Arduino is linked to. This allows for the Arduino to only have to communicate with the various sensors and any advanced control logic can be easily housed on whichever automation software is used (Node-Red in this case).
In order to communicate with Node-Red ( via node.js), the Firmata will have to be installed on the Arduino board. Once the Arduino IDE is installed on your PC, the Firmata is available in the Arduino IDE's library and can be installed ( a detailed guide is available here : http://www.instructables.com/id/Arduino-Installing-Standard-Firmata/).
Once this is complete, the Arduino board is ready to communicate with your PC running node.js.