Start.html link on the microSD card image.
There are plenty of very good tutorials and videos on how to use the Cloud9 IDE, so I have not included one here.
What the software does is, it watches an input pin waiting for it to go low. If the pin goes low, the software makes an output pin go high. This simulates an alarm panel monitoring a set of contacts, waiting for an alarm to occur.
In order to turn the alarm off, the software monitors another pin. If this pin goes low, it turns the alarm off. This is to ...