You can use your timeline to update your registration open date, your registration close date, start times for each distance you offer, as well as the actual date for your individual distances if they are happening across multiple days. If your event is only set up for one day but you are offering distances across multiple days, then you will need to contact support so that they can create a date range for you.
To edit the details on your timeline, navigate to event setup, click edit event from your admin tools.
Then click the timeline tab:
Scroll to the ‘critical dates’ section, and click the edit links next to the details to update: