functions.php

<?php
/*
Plugin Name: Example Scheduled Events
Plugin URI: https://wordpress.org/
Description: This is an example plugin to learn how to use scheduled events
Version: 1.0.0
Author: Your Name
Author URI: https://yoursite.com
Text Domain: egse
*/

/**
 * Schedule the event when the plugin is activated, if not already scheduled
 * and run it immediately for the first time
 */
register_activation_hook( __FILE__, 'my_activation' );
function my_activation() {
	if ( ! wp_next_scheduled ( 'my_hourly_event' ) ) {
		wp_schedule_event( current_time( 'timestamp' ), 'hourly', 'my_hourly_event' );
	}
}

/**
 * Hook the function to run every hour
 */
add_action('my_hourly_event', 'do_this_hourly');
function do_this_hourly() {
	error_log( 'I\'m alive!' );
}

/**
 * Clear the scheduled event when the plugin is disabled
 */
register_deactivation_hook( __FILE__, 'my_deactivation' );
function my_deactivation() {
	wp_clear_scheduled_hook( 'my_hourly_event' );
}