Hello dear student !

JEE mains exam is very important exam and the difficult level is really great . So it's nit everybody's cup of tea for sure. Firstly just make a time table and arrange yourself according to it. The syllabus of class 12th also comes in jee mains paper but the pattern is very different as it covers conceptual questions mostly. You can't only blindly focus of jee exam as 12th score is equally important so just prepare in the way so that you can cover both. First of all , make your basic concepts very clear so that you can solve the questions easily. Then give equal time to preparations of both. In this way you will be able to score good in both.

Hope this will help you