Lucas, glad you found the blog post useful; perhaps I should add this information to it.
Getting the sketch into your Arduino
Just fire up the Arduino application, paste in the sketch code, and hit "Upload." Should be all you need to do here.
Starting the Node.js Server
What operating system are you using this on? Finding out how to access your Arduino microcontroller via node-serialport will differ based on your OS.
In the source code, change the string value of
port to be your Arduino's device (once you know it). Also, the script depends on Express and (of course) node-serialport from NPM, so run
node server.js (assuming
server.js is the name of your file). Then you can access the server at