Hi Marcia,
Thanks for your note. Events Calendar PRO adds a number of cool features to our base calendar (The Events Calendar) such as recurring events, advanced views and widgets, etc. Community Events (a separate add-on plugin) adds the ability for site visitors to submit events to your calendar. Community Events can work with just our base calendar, or you can combine it with Events Calendar PRO as well. However, you don’t need PRO in order to have users submit events- just Community Events.
You can set Community Events so that all the events are marked as Pending Review, and you can edit and publish them. You can also require people to register with your site before posting events, so you then have their email on file and can contact them. Does that answer your questions?
Best,
Leah