About learning Japanese, first of all, I would like to introduce my experience: my Japanese major is CET-6 and CET-8, and I am at the international level. I studied two sets of professional textbooks and read two Korean grammar books, but neither of them passed the exam. Because Japanese and English are good enough.
I have taught others Japanese: a new Japanese course (1 to 6 volumes, this set of East China University of Science and Technology Press) comes with MP3 CD, which is very suitable for learning from amateur to professional. At first, I only bought the first two volumes. See how high your goal is in the later period. Of course, if you want to pass the first level, you must make more preparations. You should have at least two grammar books and first-class vocabulary and sentence patterns. The dictionary of China, Japan and Japan in the Commercial Press depends on your needs at that time.
I personally disapprove of using other courses, such as standard day, because it is written for training institutions. At first, the content was complicated, and the writing felt unreasonable, with too much emphasis on grammar. If you study by yourself, you will feel tired and bored easily. However, the newly compiled Japanese course is easy to learn and suitable for self-study.
My feeling is that learning a foreign language is too easy. If you have the time and ability to sell books, you can get one, but it's no use learning too much and being unskilled.
As long as you have time and money to invest in Japanese, it is not difficult to pass the first level, let alone the second level.