To book a flight on the Alitalia Airlines website, follow these steps:

1. Go to the Alitalia Airlines website (www.alitalia.com).
2. Select your departure and arrival cities, dates of travel, number of passengers, and class of service.
3. Click on the "Search" button to view available flights.
4. Choose your preferred flight and click on the "Select" button.
5. Review the flight details and choose any additional options, such as seat selection or extra baggage.
6. Enter the passenger and payment details.
7. Review and confirm your booking.

If you encounter any issues while booking your flight, you can contact the Alitalia Airlines customer service team for assistance.