Dear Aspirant,

First check out the syllabus of JEE main exam.

Study all the concepts from one source, like Coaching material/help books/etc, and once you have found something difficult to understand use some external resources like other Help books, or online explanations.

The examples in NCERT are very very important for competitive exams as they are sometimes directly asked in the JEE with slight changes.

For physics, also try to solve the exercise questions as they have really good questions and once again you should use some external sources for this.

For chemistry, do give NCERT a read in the last month of your preparation as there are many inline text questions in JEE main from there.

Important BOOKS:-

OP Tandon, HC Verma, RD Sharma, Arihant Previous year question paper, ABC Chemistry, Organic Chemistry by Morrison & Boyd, IRODOV, etc.

Here are few links for you:-

https://engineering.careers360.com/articles/how-prepare-for-jee-main

https://engineering.careers360.com/articles/jee-main

Hope this helps. Thank you.