Hello Chand, 

Firstly, you will have to satisfy the eligibility criteria i.e you should score the mentioned percentage. If you satisfy, you will have to apply for TNEA examination. Attempt it and score adequately. Apply for the counselling online and choose the colleges you want to get into. after analysis, you will be placed in the college you deserve depending on your score.

Hope this helped you.

Thank you and keep asking :)