There is a description of the level under each class in here WEEKLY CLASSES & SIGN UP. If you are in doubt about your level, please ask an instructor, or send an email to bachatahousecph@gmail.com, and we will try to guide you in the right direction.
For Intermediate 2 and Advanced there is a screening, so you need a green light from an instructor to sign up. You can get that from your instructor at your current course (talk with them in a break or after class). If you are not a current Bachata House student, the easiest way is to go to a Bachata House Sunday Social or event and talk with one of the instructors there.