Dear Saurabh, the opportunities for Desk job are posted at their official website: https://www.joinindiannavy.gov.in . Then there are positions in specific for the  serving in Indian Navy and in specific for civilians. This cannot be a part time job. If recruited, it will be a full time Central Government job. You need to appear for an UPSC entrance examination and the upper age limit for appearing for  this exam is 19 years. If you are studying MBA, you must be older than 19 years. And so you might not be eligible for this exam.