No offense meant here what so ever, so please forgive me if I do offend......You have a class scheduled in which YOU are teaching the Int'l Foxtrot and Tango? Now, if this is the case.....Why dont you get the videos, and learn the material first, then schedule the class when you are comfortable with the steps? I am ALL ABOUT people learning Int'l Style!!!! But in the same respect, this brings to mind the old chain studios where the teacher was learning the step themselves 10 minutes before they had to teach the students. If you are indeed the teacher, reschedule the class, as to give yourself time to learn and understand the steps. If I am completely wrong in understanding your situation, please ignore this LONG post!
Good luck regardless