From entrance exams to seat allotment — here is the big picture, explained simply.
Qualify JEE Main first, then clear JEE Advanced. Seats are allotted through JoSAA counselling across all 23 IITs.
A single JEE Main score feeds JoSAA & CSAB counselling for NITs, IIITs and centrally-funded institutes.
State engineering colleges admit via state common entrance tests and home-state counselling boards.
Universities like BITS, VIT, SRM and others run their own tests (BITSAT, VITEEE, SRMJEEE) with separate counselling.
This is a general overview. Exam names, dates and rules change each year — always confirm with the official exam and institute websites.