RSVPMaker is ready for WordPress 5.0. That doesn’t mean there is not still considerable room for improvement in how it integrates with the new Gutenberg editing experience, but the main thing you need to know is where to find options that have moved.
One of the goals of the new editor is to “declutter” the editing screen so that blog authors, in particular, can focus on writing without being distracted. Plugin authors are discouraged from using the old “meta box” model where lots of options where displayed beneath the main content editing area. For that reason, many of the more elaborate RSVPMaker options for setting confirmation messages, registration options, and prices have moved to a separate screen.

When you click Add New for an RSVPMaker event, instead of going straight to the editor, you will see this screen asking you to set the event date and a few other basic options up front. Note that there is also a link in the upper right hand corner that lets you shift from adding a single event to adding a template for a schedule of recurring events.

Within the editor, you will see a calendar widget in the documents tab of the sidebar that allows you to change the event date and time. This is a little tricky because that calendar can be hidden when you are editing blocks of content. Click on the Documents tab in the sidebar, and you’ll find it under Status and Visibility.
Don’t confuse the event date with the Publish date. If you set the Publish date to a future date, the post will not appear on your website until that date.

To set other event parameters, including some like event pricing that aren’t shown on the Add New screen, click the RSVP / Event Options link that appears on the black menu bar when you are logged in and have event editing rights. You will see that when either viewing or editing an RSVPMaker event post.

You can navigate back and forth between the event options screen and the editor for event content.

When you are editing an event template, an additional
“Create / Update” option appears on the black administration menu. Click there to add a batch of events based on the template to your site or update previously added events based on your changes to the template.
In addition, RSVPMaker now offers 2 Gutenberg blocks: RSVPMaker Upcoming for adding an events listing and/or calendar and RSVPMaker Embed Event for embedding a single event in a page or post. These are the successors to the shortcodes used in earlier releases (the shortcodes should still work).
Watch the video embedded above for a tour of the updated RSVPMaker editing experience.