You can define multiple races for each event, each race is scored independently, and so generates a unique results list, all participants are automatically eligible to participate in all races.

Races must not overlap, only one race may be scheduled at any given time from any event, each race has a defined start and end date/time and the races will be automatically started and stopped according to this schedule. A race may take place over a specific time window on a given day or could take place over several days or any given period of time.

When scheduling races the calendar will show all currently scheduled races for the current calendar month, races from other events are shown but will be greyed out. 

To create a new race you need to give the race a name and define the start and end date / time, you can only create races for the currently active event.