This course is recommended for people who have been studying the markets for at least a year or have taken some of our previous options courses. Having the Options Mastery #1 (Foundation), Options Mastery #2 (Verticals), and Options Master 3 (Iron Condors) should be a good enough skill set to have in order to take this course.
The calendars course will help, but getting through understanding iron condors is more important and if you have the iron condors course, you should be fine with butterflies.