In the chart settings tab, you can select the entity to aggregate and based on your entity you can select the Visualization for you charts and click on Load (Not all the entitles will have a visualisation by default).
In addition to that there are three panels, first panel is “Legend Entries” which let you define series for your charts based on CRM attributes. You can select your attribute, aggregate, Chart type and stack options from this panel per series.
Second panel is “Horizontal Axis Labels” where You can configure the Horizontal Axis. The first attribute in this section defines the X-axis label. The second attribute in this section defines the X-axis Legend and provides additional grouping for the data based on the attribute.
Lastly, the Chart preview panel where you can see the chart preview.