This is from the BA website.....
How to use a Self-Service Check-in kiosk
If you have an e-ticket booking:
Simply insert your credit/debit card into the kiosk to retrieve your booking. The card will be used for identification purposes only
If you have booked directly with British Airways, you will need to
use the same credit/debit card that you used to make your booking.
Again, the card will be used for identification purposes only
Review your booking. If you are travelling as part of a group of up to six passengers, confirm whether you would like to check in the other passengers within your booking
Confirm whether you have baggage to check in
You may check in for your return flight if it is within 24 hours
Choose your seat from the interactive seating plan
Add or change your Frequent Flyer details if required
Answer the security questions
Confirm whether a copy of your itinerary receipt is required - It is strongly recommended that you retain a copy of your itinerary receipt throughout your journey as some destinations may require you to show it as proof of travel
Collect your printed boarding pass from the kiosk. Please wait for both boarding passes if you have checked in for your return flight.
If you have a ticket with a magnetic stripe:
Simply insert your ticket to begin the check in process
Review your booking
Confirm whether you have baggage to check in
You may check in for your return flight if it is within 24 hours
Choose your seat from the interactive seating plan
Add or change your Frequent Flyer details if required
Answer the security questions
Your boarding details will be printed on your ticket
Re-collect your ticket from the kiosk. The section on the right hand side will act as your boarding pass.
There is a demo of it too
http://www.britishairways.com/travel/sscheckin/public/en_gb
Julie