Go to ROOMS click on EDIT, enter the name (e.g. Day Trip, Car...) and set the "Quantity" to the number places or items you have.
Then go to ROOMS -> DESCRIPTION SETUP - ASSIGN BOOKINGS and set '''Room Unit Allocation''' to "One Room Per per Guest". '''Maximum Nights'' sets the maximum period a booking will be accepted. If "Maximum Nights" is set to Activity the departure date is not collected and the wording of the booking form is changed to represent booking an event or day activity rather than an accommodation.
Go to SETTINGS -> BOOKING PAGE -> ROOM DESCRIPTIONS and change Unit Type to the activity you are selling.