First time NEET PG aspirant here

First time NEET PG aspirant here.Just a query regarding the counselling process,If I clear this NEET with a decent score,but I want to opt for only DNB,is it copmlulsory for me to register during first counselling itself conducted during March(MD/MS),if there will be separate counselling for DNB,then around which month is it supposed to begin for the upcoming year of 2019?