I suggest you study cultural courses carefully and wait until you pass the college entrance examination before learning clarinet.

No matter when you study, for a beginner like you who doesn’t know anything, the fastest and most effective way is to take lessons from a teacher.

If you can only study by yourself, just watch some videos on the Internet. First watch some videos explaining music theory. At least you must know the staff first, and then buy musical instruments and teaching materials. Take your time step by step, but To be honest, this method is time-consuming.

If there are students with musical talents in your school, I suggest you ask them for advice on reading music