The service is only available in English, but it is very well done.
At first glance, it seems too simple to understand, but I would say that if you write down what you want to learn, a course is automatically created, and you can create a dedicated course. The AI is there to answer your questions as well.
The same thing could be done for free with ChatGPT, but the courses displayed are more detailed and clear. Another feature of this service is that once you have created a course, you can review it later.
A table of contents is created on the left side of the screen, which seems to be generated on the first click. I find this speed slow, but it is faster than my reading speed, so it should not be a problem.