When you register for an event, you'll receive a confirmation email with an attached Calendar ICS file. That email should automatically add the event to your calendar (Google Calendar / Outlook).
If you are finding that events are not appearing on your calendar, you can do a few things to debug this:
Hit Yes on a Cosmofeed Calendar Invite:
Google has rolled out restrictions to Google Calendar to defend against spam. You can let Google know that you expect to receive emails from Cosmofeed by hitting "Yes" on the calendar invite in GMail.
Update Google Calendar Invite Settings:
You can update your Google Calendar Settings to allow receiving invites from everyone.