This plugin was reviewed in Episode 263 WP Plugins A to Z https://wppluginsatoz.com/wordpress-plugins-263/
If you would like to have a booking calendar on your site without the need for using a third party service give this plugin a try it pretty easy to set up and this video help get it clear on what you need to get the plugin working at its best for you.
Shortcode to place the form on your site
<<< be sure to adjust the widths to fit your theme..
You will also want to set a cron job to keep it clean
wget -q -O – <STIE_URL>/?_ea-action=clear_reservations > /dev/null 2>&1