What to do if my teachers are not teaching basics concepts for JEE? It’s getting difficult for me to understand things.
You should seriously consider changing your teachers. You can go either go for private tuition or try online IIT-JEE tutors. Because JEE tests your basics. Without this ground step, you cannot rise high. You should aware of simple, basic concepts before knowing the complex ones.
It is important that your basics of almost all the topics are clear and that you can tackle easy or moderate level problems in those topics, because sometimes easier questions may come from the topics which you didn’t prepare that well.
If you are not able to learn a topic or concept, read the theory again and again till you get the feel of the topic. If you find any topic boring, then incorporate new effective methods of studying to make it more interesting. You can do this by active learning where you can question yourself, make flowcharts, tables and diagrams etc.