To connect Booking.com to Preno's Channel Manager, please do the following:
Login to your Booking.com extranet.
Click on 'Account' > 'Connectivity Provider'.
Click on 'Search' or 'Switch providers'
Search for Preno and authorise.
Message Preno through the in app chat to confirm Booking.com has now been connected to Preno.
Booking.com Help Centre: Setting up and working with a connectivity provider