Settings -> RSVPMaker screen

The RSVPMaker screen under Settings on the WordPress dashboard is organized into tabs: Calendar Settings, Payments, Email Server, and Mailing List.

The main Calendar Options screen is primarily used to set the default event display and configuration options that will be applied to new events, not based on a template. (With a template, the settings of the template are applied).

A couple of notes for settings supported for backward compatibility but no longer recommended:

• Default Contents for Events – I recommend instead creating templates with content you use on a recurring basis.
• Custom CSS – you can override the default CSS stylesheet for RSVPMaker events by uploading your own to the server and referencing it here. However, I recommend instead using the WordPress Customize utility to add a few CSS tweaks (overriding anything you need to change).

The usage of the other screens is:

• Security – specify the user roles allowed to create or edit posts.
• Payments – if you will be collecting online payments, this is where you enter the API credentials for PayPal or Stripe.
• Email Server – can be used to specify SMTP mail server credentials to be used when sending email, rather than using the default WordPress functions (which can be less reliable). Alternatively, you can leave this on the default and use another SMTP plugin or a service such as SendGrid.
• Mailing List – Integration with the MailChimp service for mass email broadcasts. This is where you would enter the API key supplied by MailChimp.