What should I do to get into iist, can I get through it by clearing jee mains

If you want to get admission in IIST then you must be qualify in JEE ADVANCED with good score

Btech or Engineering course from IIST Thiruvanthapuram shall require JEE Advanced as Qualification exam for Admission in 2018 year,
as against Jee main and IIST exams conducted earlier.

For Admission in 2018, Candidate must have secured Minimum 20% marks in JEE Advanced which corresponding to 73/366 and atleast 6 marks out of 122 in all the three shbjects.

For OBC NCL candidates, at least 65/366 is required.

For SC/ST/PWD candidates, 36/366 is Minimum marks required.

The application form for Admission shall be tentatively available from third week of June 2018.
Candidates must have equally passed class 12th exam woth atleast 75% aggregate marks for General Category, for SC/ST a minimum of 65% aggregate is mandatory.

Shall you need more details feel free to ask.

Yuup all u need is above cut off good marks