Hello Jason,
Both PRO and The Community Events add-on won’t work without The Events Calendar (free) plugin. You can think of that as the core plugin, and everything else as add-ons – nothing will work without it.
There isn’t really a way to try the Community Events plugin without purchasing it, but if you have a really big problem you can always ask for a refund.
However, you may want to check out some of our documentation on this, which will give you an idea of how to integrate the calendar with your theme:
Themer’s guide to the events calendar: https://theeventscalendar.com/themers-guide-to-the-events-calendar/
Technical documentation: https://theeventscalendar.com/support/documentation
The Events Calendar with Genesis (in case this applies to you): https://theeventscalendar.com/tutorial-integrating-the-events-calendar-w-genesis/
I hope this helps!