Learn to Hack the Hack Clock!
If you don't have a working Hack Clock, start with the Hardware section of this tutorial. Once you have a working clock, we can login into it's "Integrated Development Environment," or IDE. This is a web-based IDE that you can load up in your web browser. Once your clock is powered on, you should be able to get to it's web interface on port 9003. For example - something like (but not exactly) http://192.168.1.2:9003/ if you know the IP address, or http://raspberrypi:9003 if you used the default hostname.
Once you have loaded up the web IDE, there are two ways to begin programming your Hack Clock:
Using blocks programming in Blockly, which is great
for people who are visual learners and would like to stack code together like blocks:
Using Python, which is great for people who are
accustomed to building formulae or code within a text editor:
Feel free to bounce between both editors if you like - see what your blocks look like in Python! Don't worry about breaking anything... all your code is automatically backed up whenever you click the "save" icon, and you can restore from an earlier backup whenever you wish.