An event needs to have it's title, description (main post content) and start/end times set. You may also set an event to be a whole day event, and set a location to display a map on the event.
To create an event scheduled for the future, simply set the start time to a future time.
A calendar can be displayed on a page through use of the [events-calendar] shortcode.
The plugin includes an upcoming events widget. The widget includes settings for the title, number of events and button text for the "view all events" button.
The following example will allow you to edit the schema.org event description markup.
add_filter( 'the_content', 'replace_markup' );
function replace_markup( $content ) {
$content = str_replace( '<div itemprop="description">', '<div itemprop="something-else">', $content );
return $content;
}