Hello.
In the Booking Calendar (Free) version, you can insert the booking form with calendar into the post and there visitor can select the date(s) and make the booking. After this, those date(s) become unavailable in this specific calendar in this booking form.
Booking Calendar (Free) version support only one default booking resource (calendar). Please note, you can also activate the “Allow unlimited bookings per same day(s)” option at the General Booking Settings page in advanced section, if you want to set any days as available in calendar. Your visitors will be able to make unlimited bookings per same date(s) in calendar and do not see any booked date(s) of other visitors.
In the paid versions of Booking Calendar, possible to have multiple (unlimited) number of booking resources (calendars). Please read more about this here: http://wpbookingcalendar.com/overview/#booking-resources
Please read the general instruction about usage of paid versions of Booking Calendar: http://wpbookingcalendar.com/faq/general-usage-instruction/
If you need to have 2 calendars for the different booking resources and one booking form for ability to book 2 booking resources during one booking process, then please check this article: http://wpbookingcalendar.com/faq/booking-many-different-items-via-one-booking-form/
Kind Regards.
