Hi Yvonnie,
That message is a bit confusing, since Event Aggregator is actually a separate license but not a download…Once you enter your EA license, you will see the option to import from other sources, but there isn’t any other plugin that you need to install.
I do want to point out that for any of our premium plugins, you also need to be running our free plugin The Events Calendar. I know that you recently switched over to Events Calendar Pro. Once you install and activate it, you should see a space under Licenses to add your Pro license. This will allow you to update the plugin in the future.
You are correct that we do break up the functionality into different plugins, which allows users to only pay for what they need. Many users only need a specific piece of premium functionality, so we do it this way to prevent users from having to pay for things they will not use!
Please let me know if you have any outstanding questions/issues I can help with!
Thanks,
Jennifer