Thanks for all the replies. I have two questions. They might be really stupid, but this is my first time flying alone internationally as well as my first ever connecting flight.

1. How do I find out what terminal the flight leaves from?
2. Do I have to go through customs or security or anything like that?

Edit: In reply to moondog, Ideally I would be in by noon the next day but it's not the end of the world if I'm not. The flight to Copenhagen is scheduled to arrive at 5:00 PM the first day so that should leave plenty of time. Also, it would be on the same ticket with Air China.