I don't have enough  marks in jeemains 

hii buddy. 

Since you are hoping to get confirmation in Thapar Institute of Engineering and Technology, I'm accepting you got your JEE Mains result. 

Kuddos on passing the initial step and passing JEE Mains. 

Here is a diagram of what takes after straightaway, yet first check whether you satisfy the accompanying criteria. 

To be qualified for affirmation 

The applicant 

has passed 10+2 or equal examination with no less than 60% imprints (55% for SC/ST hopefuls) in total of three subjects, to be specific, Physics, Mathematics and any one subject out of Chemistry, Biology, Biotechnology and Technical Vocational subject OR Minimum 60% (55% for SC/ST competitors) stamps in a Diploma perceived by AICTE or a state leading group of specialized training of no less than 3-year span. 

has secured no less than 72 total imprints (54 marks for SC/ST hopefuls) in JEE (Main)- 2018. This condition might not be appropriate for the PGN, GoI, JKM, JK understudies and N-E understudies as specified at statement 1.3). 

Or on the other hand 

has passed 10+2 or comparable examination with no less than 80% imprints (75% for SC/ST applicants) in total of three subjects, to be specific, Physics, Mathematics and any one subject out of Chemistry, Biology, Biotechnology and Technical Vocational subject

all the best