If you have never studied yoga and started from scratch, then I suggest you find a professional training school to study. If you have studied the basics before, you can go directly to the promotion class. Because there is no foundation, you will find it very difficult to suddenly learn the promotion course.
To become a qualified yoga instructor, we need a long time, not just a day or two. I also have a lot to do with myself in practicing yoga. As the saying goes, it varies from person to person. Some people learn things faster and have better flexibility, and students adapt quickly. Some people are stiff and need long-term exercise.