For you to be able to get the full picture of your app, you need a way to collect the insights you encounter. For this you use and take time-based snapshots of your visualizations. The snapshots you take represent the state of the visualization as well as the type (for instance a bar chart).
When you have taken snapshots of a specific visualization you can access them via the visualization's snapshot indicator: . From there you can decide which one, or ones you would like to keep and use in your coming stories.