Pour la a :
To check in for your flight: Visit your airline's website as soon as 24-hours prior to the departure of your first flight. Use the confirmation number in your online account to check in. You will also be able to view your seats and, if permitted by the airlines, confirm your seating preferences.
Pour la b :
Once you've completed the check-in process, you can print your boarding pass, have it emailed to you (so you can show it at the airport on your mobile device), or access it in a mobile app. If you don't have access to a printer or a smartphone, you can print your boarding pass once you get to the airport as well .
Désole je sait pas pour le reste ...