First, you must define Booking.com properties in "Xero organization config".
You can find the property ID in Booking.com Payout file in the column "Property ID".
Next you have to define the accounts n the "Account mapping config". You can find the accounts of type "Booking.com" at the end of the account list. There are four accounts, that must be defined.
All transaction are booked against "Clearing Account".
The last step is to start the import of Booking.com payout into xero. There is a new menu "Booking.com Payouts":
You must select the Booking.com Payout file. Simple click at the field "Booking.com Payout File". A new File-Select-Windows will be opened. If you have selected the file, you can import the Booking.com transaction from the file into xero. As by apaleo transactions, for each booking data will be created.