Lack of activities in notebook walkthrough

[psychemedia]

The current walkthrough of the Jupyter notebook doesn't explicitly describe any activities or exercises, although the expectation is that the instructor would invoke activities/exercises to practise the elements as they are introduced.

We should include explicit structured activity/exercise statements designed to practise each element, allowing participants to build up a notebook over the course of the walkthrough that acts as personal reference document for them for how to use the notebook.