Give me process to join Indian navy after passing 12th grade and also give me required eligibility for it ?

you can join Indian navy after passing 12th grade with science stream examination through NDA examination organized by UPSC ..

Eligibility:
For Air Force and Naval Wings of National Defence Academy
You should be 10+2 passed with physics and mathematics subjects. Candidates who are appearing in the 12th class under the 10+2 pattern of school education or equivalent can also apply.

Age limit :
The candidate’s minimum age is 16 1/2 years and maximum age 19 years for the NDA exam.

(a) Nationality:
A candidate must either be:
A citizen of India, or
A subject of Bhutan, or
A subject of Nepal, or
A Tibetan refugee who came over to India before the 1st January, 1962

Exam Dates
Date of notification : 21 JUNE 2014
Last date of form submission : 21 JULY 2014
Date of NDA exam is 28th SEPTEMBER 2014