Hi saurav as u have a time period set!  first concentrate on which subject to focus on and work hard on the points that you feel you are weak .. make a proper schedule plan and follow it regularly and also make a proper time management so that you can complete the studies and be prepared at the time of the exams so to avoid chaos!

here is the link where you can get to know which books to refer 

https://www.google.co.in/amp/s/engineering.careers360.com/articles/best-books-for-jee-main-2019/amp

If u still have any doubts please feel free to ask 

all the best

Hi Saurav,

See to prepare for JEE 20 months are enough.

The Books you can consider are as follows:

• For Maths, RD Sharma
• For Physics, HC Verma
• For Chemistry, Pradeeps or any other

These ones are basic books to understand the concepts, once you finish that you should do just go and start practicing as soon as possible.

Good Luck !!!