Slightly strange request.

I know that a few people on here know Japanese and so hopefully you’ll have spent some time at a Japanese school.

Basically I’ve got an interview on Monday about teaching English in Japan for a year and have been asked to prepare a five minute, multi-part presentation bit.  For the first part (lasting 30 seconds!) I have to greet an imaginary class of Year 1 High School students as if at the beginning of a lesson.  My research has lead me to understanding that Japanese kids tend to stand up, ask to be taught, bow and then sit back down, but what does the teacher do?

Preferably ideas which fill 30 seconds