If you are a high school graduate now, go directly to the intermediary to apply for a visa to study in Japan or study abroad, contact a language school and come to Japan to study in a language school. If you have the foundation, hard work, need 1 year, or your own Japanese level is already high, then what you need is to come to Japan in this way. Then, after graduating from a language school, you can choose to enter a university, college or specialized school in Japan. If you like animation very much and are determined to make it your career, then it is recommended to enter a special school, which is short in time and efficient. Many special schools are linked to Japanese animation companies.
As for exam subjects, sketching and Japanese, these are basically three points, as well as interviews.
In fact, many schools in Japan do not require test scores, and there are no tests. In Japan, the most important thing is the interview, which shows your personal temperament and talent, because the Japanese think that the test score is meaningless in practical work, and the score is valuable only in China, because there are too many people, so there has to be such a meaningless thing.
So do many universities in Japan. For international students, passing Japanese is enough. There is only one interview for all exams.