CBSE 12th

You have mentioned that you are doing private coaching in Kota. That means you are already in coaching guidance. They might be given you a work schedule. Well answer to your question is from January 16 onwards you start study for your boards instead of Mains. How? I assume that you are studying in CBSE. So you have 5 subjects. Okay by January 10 date sheet will be available. Look for the first exam in that Time table. For that subject ( mostly English ) study last one week just before the exam. Now you have 4 subjects. From January 16 allot one week each to one subject. In that write as many sample paper. Correct each paper from your teacher. You need a lot of writing practice. Aim to finish each paper in 2.45 hours.
I followed this for my son only last year he got 98.2%. You will find few extra days in my plan. They are called buffer period. If some guest come to house and you miss the plan you can utilise buffer period.

Minimum Eligibility to apply for PG courses at Symbiosis International is at least 50% marks in Graduation from a recognized university or equivalent.
There is a provision of 5% relaxation for SC/ST category students.
For course specific eligibility, refer to the university prospectus.
Admission Process
Admission to the university is granted basis merit earned in academics and entrance exam. The candidates are required to appear in the SNAP test for PG courses and SET for UG courses.
Post the entrance examination, selected candidates will have to appear in GD-PI round conducted by each of the 15 Symbiosis International schools. Admission will be granted on the basis of a candidates overall performance and academic score.
For Engineering and Health Sciences (UG), a candidate is not required to appear for SET if he / she has valid score of other exams like JEE (Main) and MH-CET. Such candidate may apply directly to the concerned institute.