First step do make and account in the www.dgshipping.com its an free account with your INDOS no and a password. This is the main source for all the marine engineering or any one easy way to update to mmd or ilo. keep update your experience and certificates you recieved.
Once, after the pre sea training you need to go for an post sea training for more than 6months.
Its much better to have atleast two or more days than required.
you need to additional courses after your pre sea training.
Important: Dont forget to get your sea time from your chief engineer.
On completion of your advacned courses you can go for class iv examination. . at you convinient MMD, India.
i will make you more clear about the exams and so on asap.