Default Occupants allows you to have the number of occupants in a room type preselected on the Personalise Your Stay page of the booking process. This saves most users clicks when going through the booking process, simplifying it.
If the default number isn't what the user wants to select, they still have the option to amend with the - / + buttons.
To set up:
In the booking engine under ADMIN -> ROOM TYPES, edit the room type you want to amend.
Beside the Max Occupant for each type, select the default number from the drop down.
NOTE: once a default occupancy has been selected, this will allow the user a min of 1 of these occupants, e.g. if you set 2 children as default, you can only reduce this to 1, so must add a child to the room when booking. If you allow 2 adults only to check into a family room, don't set default occupants for child/infant occupants.