When you visit https://www.iac.org/contests you'll see a blue 'Register' button next to every upcoming event. Just click it, fill out the required information, and submit the form.
To see who else has registered for an event, go to https://www.iac.org/contests, click on a contest name, then click the blue 'View Pre-Registrations' button. Contest organizers will see complete details, while everyone else will see basic info (name, category, etc.) Contest organizers will also have the option to...(read more)