Hello!

I suggest you a book a book named University of Delhi: B.Tech (Information Technology & Mathematical Innovations) Entrance Exam Guide written by R Gupta.

This is a good book. It is also available online.

You must solve the previous year sample papers of DU B.Tech.

Try to Solve sample papers.It will help you to get an idea about your preparation level, weak areas to work on and more. And revise Ncert thoroughly.

Thankyou!

All the best for your future!