After ticketing procedures are completed, you receive a confirmation e-mail with your ticket. Starting roughly 24 hours before your flight, you should enter the same name and surname that is in this e-mail, along with your e-ticket or reservation number, through the online check-in link. You can then choose your seat from the seating plan of the plane. However, please note that for some airlines choosing the seat in advance is optional and may require you to pay a small fee.