Hello Applicant!!

After your class 12th, or while you are continuing class 12 you first you need to apply in JEE Mains exam followed by qualifying it with a good score and then if you achieve the cut off marks you can apply in JEE Advanced, after qualifying which you can apply in IITs. To get an overview regarding the possible questions, you need to be thorough with the question paper of JEE Advanced of last five years, appear in frequent Test Series conducted by different Educational institutions and build up a self confidence. You can take help from Organic Chemistry books by Morrison and Boyd, Physics books like H.C.Verma.

Hope it helps!!!