Dear Aspirant,

For JEE advanced you need to get hold on all three subjects as JEE advanced have overall cutoff and also sectional cutoff, therefore students have to clear each subject separately.

Now to prepare for JEE you can make a timetable with 2 hours per subject. However, if you like chemistry more then you can give more hours to chemistry in initial days of preparation. But you have to prepare for all three subjects.

The first thing you should do is check out the syllabus in the links below.

Here are some links for you to get started:-

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

https://engineering.careers360.com/exams/jee-advanced

https://engineering.careers360.com/articles/jee-advanced-2020

https://engineering.careers360.com/articles/jee-advanced-syllabus