Hello aspirant,
For Tamil Nadu engineering college procedure for admission is:
Eligibility-50% marks (general)
45%(backward)
40%(mbc&dnc)
35%(sc,st)

Then submit application form with the documents along with dd of application fee.
TNEA councelling form can be issued for those who applied from other states.
For further detail you can download the PDF of the respective it is available easily.
Hope it helps.