How to select multiple times as I saw on official screenshot

Dear friends,
last time I was read documentation I saw some screenshots from plugin.
I saw this one:
https://easy-appointments.net/wordpress/wp-content/uploads/2018/04/Screen-Shot-2018-04-15-at-9.06.07-PM.png

In this screenshot you can find basic form, but with option to choose more times at once.
Is that any advanced, or paid feature? Or how can I select multiple times at one day?

Thanks for your help and have a nice day! 🙂