IIT

You have selected a very good option to prepare for JEE from my point of view. You have to follow few steps:
1. Gather proper material for your preparation: Go online and order JEE Mains material' from career Point Institute, then do order for JEE Advanced material from Allen Coaching. Buy the material only for current courses.
2. Now, how to study those courses? If you are in high school then study whole one chapter from your textbook then go through the objective questions of JEE Mains after solving JEE Mains questions, go for advance questions from JEE Advanced (Allen). Mark the important questions that will help you at last for revision. At last, you just go through the marked questions. Solve the whole material at least 2 times or more than that. Don't refer anything apart from the material I told you. Study at least 6 hours and on every Sunday solve one question paper in 3 hours (time foundation is compulsory) after exam go through the solutions and learn from your mistakes. Make notes of your problem keep this, it will also help you at last for revision. Observe the periodic table horizontally and vertically, learn square root till 30 and cube root till 20. At last keep practising, don't stop till you get selected. My best wishes are with you. If you still have any query ask me. I will help.