The problem of learning Japanese is a cliche. Glad to hear that the novice asked. Please refer to the supplementary section.

If you study hard for 2-4 hours every day, you will definitely reach the level of 1. At the same time, you should know that CET- 1 is not a strict method to test the strength of Japanese. As a Japanese major, I think everyone will memorize a lot of vocabulary, remember sentence patterns and practice listening before the exam in order to cope with the exam. In fact, if you want to learn Japanese well, it's best not to take an exam as the goal, but to focus on application after learning the basic knowledge. A lot of things in the first-level exam are not used in actual work and life, and it can only be said that it is a kind of knowledge accumulation. I suggest you lay a good foundation, and then pay more attention to business and daily conversation. This is also necessary for listening and speaking. Mark Day is not a very good book. Although it is used in many schools outside, it is generally not recommended to actually learn Japanese. Buy new teaching materials, such as those published by FLTRP. In addition, I recommend business Japanese from Dalian University of Technology as a conversation textbook after you learn the basics well. Finally, as to whether you can't teach yourself the basics, absolutely not. Many people around me are not Japanese majors and have never taken Japanese classes, but their Japanese level has reached level one or above through self-study and they are fluent in conversation. The key is interest and perseverance. Bless.