Hello Vishal Verma,

Jee Advance(IITJee) is entrance examination for getting Admission into IITs and ISM Dhanbad.

Students usually prepare at least for 2 years but 1 year is also a good time if spent in Productive way. One needs to have a good hold on basics so I would recommend you to start with 11th (intermediate 1) books then only move to 12th. Start with NCRT books for PCM. For chemistry, NCRT is must read.

Moreover, it depends on a student in which subject he holds good strength and students usually target at least score 1 or 2 subjects properly. Do some groundwork then come with your subject with good strength try to score as much as possible in those particular subjects.

There are a number of books in the Market but it depends on students what they like and for physic students usually start with H.C Verma, chemistry with NCERT and Maths with Arihant publications. Remember this is leveling up and you will surely upgrade your material with coming time.

For time management it again comes to the strength you hold on a particular subject. Also, your 12th boards are important to give it time too. 

I followed the rule of 4:2:2:2 rule for Maths, physics, chemistry, and Boards respectively however I recommend you to make one for yourself.

If you haven't started preparing yet, I believe you should start Asap.