These are my slides from my workshop at Twitter Math Camp on Powerful Ideas in Math via Programming.
I recommend opening up the speaker’s notes and trying out the challenges and activities given. You can use Blockly to experiment with different code, but my suspicion is that you will learn more from the experience if you don’t run the completed code until you are pretty sure you know what it does. Let me know how you do with the challenges and activities if you try them. It will also be useful for you to frame your activity with, "what does affordances for thinking does this programming environment offer?"