Hey @dlberkson6! Automations cannot be triggered by date/time events at this time; those types of events can only be within the automation. That said, as a general rule, we'd also typically recommend creating a new automation for each webinar — this helps keep the data clean & separate.
In this case, I'd actually recommend reaching out to our team at email@example.com (or via the in-app messenger in your account) with a description of this issue and examples of what automations you're currently using for this (if any). One of our Product Specialists will be able to take a look at your account and offer more specific suggestions based on that!
In addition, I'm also going to include a couple of resources below that might help clarify further how automations work at a higher-level:
Last but not least, we also have this Host a webinar8 visual automation template that you might be able to modify for your purposes :)
I hope that helps!