Hello @TamaraL133 ,
My team checked with the webinar team, and there should be links to add a reminder to your Google Calendar on both the registration confirmation page and in the confirmation email. However, depending on the webinar you registered for, they have noticed one webinar series that's currently experiencing an issue that can cause difficulties adding the reminder to Google calendars. There is a ticket in with the vendor of the webinar software to address it.
If the webinar is happening relatively soon, I'd advise creating a manual calendar reminder using details from your confirmation email or the webinar site itself.
Our webinar team has provided a follow up to this. If you happened to register for the webinar that's experiencing issues with the Google Calendar link, you can email email@example.com and they will manually send you a link, or they mentioned that you could use the iCal option to add it manually into your Google Calendar.
Sorry for the additional steps and the trouble. This just seems to be something happening with just this one webinar.