Hi Aarya ,

the gmvss marksheet will not be accepted by DTU . All the IIT aspirants have to sit for JEE Main and afterwards, JEE Advanced. Only the top 150,000 scores in JEE Main will become eligible to sit for JEE advanced. The selection of candidates is made on the basis of JEE Main All India Rank of the candidates. 

   40% weight age is on JEE score and 60% weight age is on class 12th exam score.

   The age of candidate must lie between 17 to 25 years as on 1st October 2017.

JEE eligibility criteria apply to the DTU for admissions to their undergraduate programs. Based upon their score and rank in the JEE Main exam, shortlisted candidates are called for counseling .

all the best