To get admission into IIT, You need to qualify JEE Advance which is going to be held on May 19,19. 

First you need to make sure that you score more than 75%in 12th. Now you need to appear for JEE Main, which is held twice a year in the month of January and April. If you have not for applied for JEE January then apply for JEEApril in tge month of February.once you qualify JEE main . you will be eligible to appear for JEE Advance, qualify it with ranks under 8k to get admission into IIT.

Hey.

To be Eligible to take admission in IITs you will have to satisfy at least one of the following two criteria- pass 10+2 orequivalent examination with an aggregate of at least 75% marks. If you belong to the SC/ ST and PwD category then you need the aggregate of minimum 65% marks. Or be in the top 20 percentile of your board, in your case of PSEB. Other that that your chances of admission will depend on your rank in JEE Advanced.

Best of luck!