DTU takes the admission through JAC Delhi counselling on the basis of JEE Main score. As per the eligibility you should have minimum 60% marks in Physics, Chemistry and Mathematics taken together. English must be one of the compulsory subjects in the qualifying exam.

Distribution of seats:

In total seats, 85% seats are reserved for Delhi Candidates.

Remaining 15% seats are there for the outside Delhi candidates.

As you told that you belong to Bihar then you will be eligible for 15% quota seats which is for outside Delhi Candidates.

After qualifying JEE Main Entrance Exam, You need to register for JAC Delhi counselling, which is expected to start from the third week of June. 

You can also refer the below given article for the complete information

Https://engineering.careers360.com/articles/jac-delhi

Good Luck!