For Bachelors in engineering or bachelor in engineering and technology you can apply for TE S Technical Entry Scheme

To eligible for this you have to complete class 12 with at least  70%  in physics chemistry and mathematics also there is age limit also from 16.5 years old to 19 years old

After clearing this you have face an interview done twice in a year called ssb interview

Hey buddy,

As to do military engineering you must have passed your 12th examination with PCM then only you are eligible for the  program and must have scored 70% marks and your age must be 16.5 years to 19 years  OR you can either apply through  technical entry scheme basis.

Hope it helps.

All the best.