Hello greetings

Once you qualify JEE advance then the process of sealed allocation begins in the process of seat allocation you will be feeling choices according to your preference suppose you are interested in Computer Science in Engineering at IIT Bombay  then you will feel Computer Science and Engineering at IIT Bombay as your first choice then followed by other choices as per your preference level but feeling IIT Bombay Computer Science and Engineering is your first choice does not guarantees that you will be provided a seat in IIT Bombay Computer Science and Engineering rather it means that all the candidates choice will be considered and based upon the number of seats and their ranks they will be offered seats suppose there are 80 seats in Computer Science and Engineering at IIT Bombay and if there are  students which have better rank than you then you will not get a seat but instead if there are many students which have better rank then you but other candidates got their preference and not filled IIT Bombay computer science engineering as First choice then you will get a seat in IIT Bombay Computer Science and Engineering so this was just an example but this is the process of seat allocation so if you will score a better and get a better rank in the choices you feel would be considered more that is your chances of getting your initial preference is higher.

Hope this helps all the best

Hey Bhimanna,
It's not your choice to select in which college you want to get the admission. Admissions in iits, nits are on basis of Jee mains and advance score. Every year Jee mains and advance is held to get admission in iits and nits. On the basis of your score in jee paper you get admission in these colleges. The cutoff vary every year and is different for every colleges. Nits accept mains score whereas to get into iits you have to first clear mains and then clear the cutoff in advance paper. The cutoff for general, obc, sc and st category are different. If you clear cutoff in mains paper then you can apply for all nits and some good private colleges and can further appear for advance paper to get admission into iits.
Thank you