Once an invited participant schedules time on your calendar, their status becomes Scheduled.
This status does not apply to unmoderated studies since they don't require a calendar.
In the example below, Pierrick is a scheduled participant:
Their scheduled time will allow show up under your bookings tab:
Attended - Once a participant completes their project, you can mark them as attended. This will move them to the payment page.
No Show - If a participant doesn't show up to their scheduled time, you can mark them as No Show.
See more on the other participant status here.