The fastest way is to go to the bottom of the home page of Zumba.com and then scroll down on the left side where it says “Become a Zumba Instructor.
That is where it is located on the US page. I believe pages in other countries are now similar.
I’ll see if I can find the ZES in your region. Many of them book months in advance, especially ZES who work in multiple countries, so even if the schedule isn’t on the Zumba site, they might have a date planned they can tell you.