Are you currently in Mexico?
I’m not familiar with Mexican law or processes, but i can give you some hints about the US.
First of all, you will need to be able to provide CECs for either ACE, AFAA, or both for group exercise. Some people attend training because they want to teach a format. Others attend training because they need continuing education to keep their certifications current. You want to attract both audiences. Also, being a provider for these companies means that they have reviewed your curriculum to ensure that it meets the standards for safety and education of the instructors who carry their certifications.
In addition, you will want to come up with a brand name, marketing, etc. You will probably want to trademark your brand.
Most brands that I’ve seen that have grown lately have started from a very popular format in a local area. Grow the popularity of your format in your area. Then start recruiting other instructors to teach. Then start having trainings locally, then nationally, then….
Also, consider appearing at fitness conventions and trade shows so that instructors know about your format.
Another option is to apply for master trainer status for a company that has a barre course. For example, Lebert Fitness has a class, LeBarre, that is having a master trainer summit some time in March.
I’m not sure what the application process is, but there are several companies that do this now – calls for master trainers that are more available to the public to apply for rather than hand-picked from their personal connections.