Changes

You use a property with a special setup to sell extras to guests that have already made a booking. They will need to enter their accommodation booking number when they make the booking so the owner can ‘group’ the bookings. Set upAdjustments for your lodging property

Setup Adjustments for your property: Add a Custom Question to your Booking page SETTINGS -> PROPERTIES-> BOOKING QUESTIONS so a guest can enter the original booking id so you can link the bookings together.