As you have asked about the Indian University Entry scheme (UES) written test, I am giving you information about it, check below for the details

Final year Engineering students are eligible for induction into the technical Branches/Cadres of the Navy under the scheme.
Naval selection teams from the IHQ of MoD (Navy) and Command Headquarters visit AICTE approved Engineering colleges across the country to shortlist the candidates.

Selection Procedure
The eligible candidates applying for the entry will have to appear before a Naval Campus Selection Team for interview

The short listed candidates, based on All India Merit, are called for interview at the Services Selection Board (SSB)
The successful candidates, thereafter, are put through the medical tests.
Final selection is based on all India merit on the basis of marks obtained in the SSB interviews.

Educational Qualifications

Final year (4th / 5th year) in an AICTE recognised university with one of the following disciplines and should have obtained a minimum of 60% aggregate marks (till VIth semester):

Engineering Branch (Only Men to apply): Mechanical/Marine/Aeronautical /Production /Computer Science Engineering /Information Technology/Control /Electrical /Electronics /Telecommunication
Pilot (Only Men can apply): Any stream of BE/B.Tech (Physics & Maths at 10+2 level)
Observer (Only Men can apply): Any stream of BE/B.Tech (Physics & Maths at 10+2 level)
IT (Only Men can apply): B.E/B.Tech. Information Technology, /Computer Science Engineering/Computer Engineering
Logistics (Works) (Both Men and Women can apply): BE/ B.Tech in Civil/ Architecture
Candidates in their last semester (i.e. eighth semester) or who have already completed BE/ B. Tech Degree need not apply
Naval Architecture (Both Men and Women can apply): BE/ B.Tech in Mechanical /Civil /Aeronautical/ Aero Space /Metallurgy Architecture/Naval Architecture