Groundplan Events and Venues come pre-built with a number of pre-built fields and functions to aid in your theme logic.  

Configuration Options

Google Maps v3 Embed API Key to enable venue map functionality.
Enables the ability to categorize your events by a taxonomy (mc_genre)
Label for the default taxonomy (default is "Genre")
(boolean) Uncheck to unenqueue the default Groundplan CSS flexbox styles. Default is on. These base styles can be included and still overridden in your theme file with a skin, so disabling the base styles is mostly for complete rebuilds of the calendar styles

Event fields (postmeta)

(text, max length 18 characters) An abbreviated title. If there is a value, the short title is used in contexts with limited space, such as the event calendar. If there is no value, the event title is used.
(text) an optional schedule of performances, for use with a simple event schedule.
(url) A general ticketing url for the entire event, used for general "Buy Tickets" links. It's best practice to supplement this general link with performance-specific ticket urls at the so that your patrons click as few times as possible during the checkout sequence
(text, optional) A sort order for the event.
(text) A price range for use in event summaries / overviews.
(textarea) a byline for the event, optionally including marquee credits.
(text, optional) Running time for the performance.
SINCE 1.1.0
(int, optional) Running time in minutes for the Performance.  Used by the Grid / Festival Hourly calendar.
(text, optional) Disclaimers / appropriate ages for the performance, for use on the event detail page.
(text) Default message to display on the calendar when a performance is sold out. Defaults to "Sold Out"

SINCE 0.8.5 

(text) If set, will display on the calendar when an upcoming performance is of the "Free" Performance type. Default is empty.
(image) Images for page headers, sliders, and social media sharing.
(image) Smaller format image for use on monthly and agenda calendars. If set in the event, will automatically display in calendars other than single.
("On" or "Off") Use this setting for shows that do not have officially announced dates. Turning this setting on removes the event from the event calendar, and also forces the 'Display Date Override' to appear instead of calculated dates.
(text) Set this value when hard run dates have not yet been determined, or to change the default display of calculated dates. (eg. \"Spring 2013\")"
(calculated text). Long format event run date range, automatically calculated on save_post from performances in the event and vague dates settings.
(calculated text). Short format event run date range, automatically calculated on save_post from performances in the event and vague dates settings.
(calculated text). Sortable event run date range, automatically calculated on save_post from performances in the event and vague dates settings. Used as a column in event admin views.
(wysiwyg) A short format summary to market the event on home pages and event summaries.
(wysiwyg) A complete description field for display on the event detail page. Can include features like image galleries and videos
(calculated timestamp) First date of the event, calculated by performances. Used to filter event queries.
(calculated timestamp) Last date of the event, calculated by performances. Used to filter event queries.

Event Performances (posts2posts relationship and p2pmeta)

Groundplan bundles the efficient Posts 2 Posts relationship functionality to generate connections between Events and Venues.  Performances can be loaded into WP_Query objects to be used in your templates.

$post → performances
Default array of performances in the event

If you're using the PatronManager Add-On, Performances are automatically created from your PatronManager event instances. They are then saved in WordPress, even when they expire on PatronManager.
[performance] → starttime
(timestamp) Start of performance.
[performance] → eventtype
(select) Performance, Preview, Extension, Sold Out, Free, RSVP, Pre-Show Event, Post-Show Event, Talkback. Displays as the "Performance Note" on the calendar. When set to "Sold Out", unique classes are applied to calendar event blocks to allow you to modify CSS for sold out events, and ticket links are disabled for that performance.

If you're using the PatronManager Add-On, Sold Out status is automatically updated from ticket availability data.

Eventtype options can be updated using the xdgp_event_instance_arguments hook in your theme.

[performance] → ticket_url
(url) URL to deep-link to ticket purchasing for this specific performance. Used by the event calendar to make the purchase process more efficient.
[performance] → description
(html) Only available in public HTML data.  This is a typically blank field available for customization of API data on the performance level.
BETA Description is displayed when present in Mini calendar details.

Venue fields (postmeta)

(textarea) full address of venue location.
(url) Embed URL for the Venue location. Requires a Google Maps Embed API key to be set for your domain
(text, optional) Venue capacity for use on venue detail pages
(wysiwyg, optional) Description of venue for use on venue or connected event detail pages.
(wysiwyg, optional) Navigation directions to the venue, for use on venue or connected event detail pages.
(select) Determines local time for the venue.

Extending Groundplan Fields

Groundplan Pro bundles the popular WordPress plugin Advanced Custom Fields Pro.  It's easy using the Custom Fields menu to extend events and venues with additional field types.  Common needs are additional Event images that are used in different contexts, such as a home page slider.  

It is also possible, using ACF actions and filters, to modify or disable the default fields that come with Groundplan Pro.  However, you may want to review plugin code before disabling core features.

If you already have ACF or ACF Pro installed on your WordPress site, your copy of the plugin is used instead of the bundled version in Groundplan Pro, to help server efficiency. Groundplan Pro requires at least ACF 5 +.