hello mukesh kumar,

i think you are asking about IIST b.tech admissions.for that you must clear JEE ADVANCED,before jee advanced you should get qualified through jee mains.please refer this link to know more about b.tech admissions in iist,

https://engineering.careers360.com/articles/iist-btech-admission

copy above link and paste it in the address bar of your browser.

all the best!

I Hope this information will be useful to you.

if you need additional information,let us know to help you.

Thank you!!!:)