scholarship

First of all, congratulations to get good marks in your 12th. Taking admission in NIT or IIIT is dream of many students in India. To get admission in NIT or IIIT, you need to appear for JEE Mains exam conducted by NTA every year. Every year 7-8lakh students appear to give this exam
There are 31 NIT and 25 iiit in india in which there are approximately 25,000 Sets for B.Tech in all NIT and approximately 5000 seats for B.Tech in all iiit. As you got 89 percentile in JEE Mains score, to get admission in NIT or IIIT bassd on your this score, it depends on that from which category you belong like general, OBC, SC, ST, PwD
If you are from general category, then you will not get any NIT and iiit
But if you are from SC or ST or PwD category, then you will surely get any NIT or iiit with best B.Tech branch as per your choice.

Central Sector Scheme of Scholarship for College and University Students. The Scheme is in operational since 2008. The objective of the scheme is to provide financial assistance to the meritorious students having family income of less than Rs.4.5 Lacs per annum, to meet a part of their day-to-day expenses while pursuing higher studies. Annual target is 82000 scholarships per year (41000 for boys and 41000 for girls) which has been divided amongst the State Education Boards based on the State population in the age group of 18-25 years. Students who are above 80th percentile of successful candidates in the relevant stream from a particular Board of Examination in class XII and pursuing regular course and not availing benefit of any other scholarships, are eligible to apply under this Scheme. The rate of scholarship is Rs. 12,000- per annum for the first three years and Rs. 20,000- per annum for the fourth and fifth year. The Central Sector Scheme of Scholarship for College and University Students is covered under the Direct Benefit Transfer (DBT) w. e. f. 1.1.2013. The scholarship is disbursed directly into the savings bank account of the scholarship recipients by DBT mode using PFMS gateway.

There are two ways to take admission for M.Tech. First one is through the GATE exam and second one is sponsored admission. Those who take admission for M.Tech. Through GATE exam, you will get stipend of INR12.4k. There is no stipend for sponsored M.Tech. Students. M.Tech.
For taking admission in IITs for M.Tech. Through GATE exam, you have to apply for each IIT individually. There will be interview after shortlisting and final selection is after interview. M.Tech. in NITs.
For taking admission in NITs for M.Tech through GATE exam, you have to go through the CCMT (Centralized Counselling for M.Tech) process. In this process you have to fill common option form for all NITs. There will be four rounds of admission and 4th round will be counseling round.