You can use widgets to quickly see the participants of your event grouped by specific fields/stages.
The "Participants by stage" widget is used to see what stage all of your participants are currently in, those stages are the ones that were set up in the Workflows module.
Example: We want to see the percentage of participants invited to the event / who registered to the event / who actually arrived to the event / who cancelled / etc.
In the Event dashboard module, click on the + button to add a new widget and select "Participants group by stage", click Save.
The widget will then be added to your dashboard. By clicking on its Actions menu (3 dots) you can edit the name of the report and its visual representation.