1. Check on the Internatioanl Affairs Office's website, to see what are needed for application.
2. Taking TOEFL exams:
TOEFL or other language exams are required for application, one should take at least once before applying. Normally the application process starts in December, remeber to get your TOEFL results before it. Besides, great TOEFL scores will play a really important role while applying. Just make sure to excel in it.
3. Your average grades at NTU
One's average grades at NTU also play an significant role in application.
4. Taking the auditions/exams by International Affairs Office
Well, I am not sure whether this part really matters. Personally I did the exam badly, but my resume, TOEFL scores, and grade papers saved my life.
5. Sending out choices for schools if you lucky get past the audition.
School choices depends on oneself and the limitations bounded by contracts between NTU and exchange schools. There is not much to talk about. Just choice as one wishes.