Clear multiple cron jobs created by Google Reviews Business plugin.

clear-grp-cron-jobs.php

<?php
/**
 * Clear multiple cron jobs created by Google Reviews Business plugin.
 */
function clear_cron_jobs() {
	$crons           = _get_cron_array();
	$hook            = 'grp_auto_save';
	$args_array = array();
	$new_cron = array();
	foreach ( $crons as $timestamp => $cron ) {
		if ( isset( $cron[ $hook ] ) ) {
			$args = serialize( array_values($cron[ $hook ])[0]['args'] );
			if ( in_array( $args, $args_array, true ) ) {
				unset( $cron[ $hook ] );
			} else {
				$args_array[] = $args;
			}
		}
		if ( ! empty( $cron ) ) {
			$new_cron[ $timestamp ] = $cron;
		}
	}
	_set_cron_array( $new_cron );
}

add_action( 'shutdown', 'clear_cron_jobs' );

Hi there. Sorry for the newb question. But where do I place this code? And how do I get it to run? Thanks!