What is the fare for the "Child" and "Infant" categories?

A "Child" ticket is discounted by 25% from the full fare, while an "Infant" ticket is discounted by 10% of the full fare.

How can I find preferred flight schedule?
Where can I purchase airline tickets?
When booking a ticket, I incorrectly indicated the name of the passenger (last name, passport number, etc.) – what shall I do?
Can I choose any seat when purchasing a ticket?