Each organization can configure when they allow activity tracking. If you do not see the option, it may be due to the date of the event. For example, some organizations may configure the activity tracking features of their application to be enabled 30 days before an event date.  if your event is more than 30 days out you won't be able to connect just yet.

You may need to reach out to the organization to see how their app is configured. If you need additional help, please let us know.