Be prepared and be honest. Your talents and experience is important to get through the online test, but it is your character that is on display in the in-person interview. If you know the answer, great! If you don't know the answer, don't pretend to. Come with questions for those that you'll be meeting, and make sure they're sincere interests for you to know.
You need to "think big" and tell us how you could help in this new position.
Help answer questions real people are asking about your company. Your answers will be 100% anonymous.
The person asking the question will be notified of your answer, and it will be posted publicly. Your identity will be kept private