You can take admission in an IIT through the Joint Seat Allocation Authority (JoSAA) counselling.

1. Eligibility: You must have qualified in the JEE Advanced exam.
2. Registration: Register on the JoSAA website and fill in your choices of IITs and courses.
3. Seat Allocation: JoSAA will conduct multiple rounds of seat allocation based on your rank, choices, and seat availability.
4. Reporting: If you are allotted a seat, you must report to the allotted IIT within the specified time frame.

For more information, please visit the JoSAA website or contact the helpline numbers provided on the website.