Here are a couple of good ways to create links to calendar events:
You could create and publish an event in google calendar and send a link for people to add themselves to it. See the second section on this page: https://support.google.com/calendar/answer/41207?hl=en
You could also create a calendar event file using something like this: https://ical.marudot.com/ . Once you've done that, just upload the file and give it a banner image which works for you:
