Hey there, 

First and foremost, you should apply for TNEA/TANCET examinations choosing the examination of your choice. Then you'll have to write the applied examination and ace the examination. You should meet the eligibility requirements provided by the respective college. Apply for the counselling. And chose the college of your interest. 

Before applying  the examination, do check if you're meeting the eligibility criteria for applying the examination. 

The application forms are available online in the official website. 

Hope this helped you 

Thank you and keep asking :)