Are you hosting an event that spans two days where participants may race multiple times?
Do you allow a participant to race twice in the same event, e.g. in two different categories?

The recommended method is to create a separate registration for each race, and then tie to regs together using a series registration.  Example:

Participants can select one or multiple races by clicking on the check box on the left, and proceed to fill out the reg page for each.  Fields that are identical (e.g. name, email address etc.) will be auto-copied for 2nd and subsequent regs.  Participant will make one payment that covers all events selected.

CREATE A REG FOR EACH SEPARATE RACE

Navigate to Organizers / My registrations
Click on the "Add an event registration"
Create a separate registration for each individual race
- If multiple categories are racing together, then these should be under the same reg
- Create separate regs for SUP Sprint in the morning and SUP 10km in the afternoon
Create the reg for the first event, then click “Use as template” to copy the setup to others

CREATE A SERIES REG

Navigate to Organizers / My registrations
Click on the “Add a series registration”
Add the separate registrations to the series
Use this option to allow participants to register for one or multiple races

For each separate registrations, set “Event visibility = Private”
For the series registration, set “Event visibility = Public"
Publish the series reg link as the (only) way to register for the event.

The benefit is that you’ll get an automatic start list for each race which can be downloaded directly to the app.  No file downloads or uploads required.  The series reg also allows to to offer discounts for signing up for multiple races, e.g. 10% off if you sign up for 2 or more.