Hello!

There are two ways to get admission for a law degree.
1. After your Intermediate exams (Five Year Law Course)
2. After Graduation (three year law course)

Since you have completed your graduation the second option is for you. 
Every year universities throughout the country conduct entrance examination for the three year law course, notable among them are BHU, ILS Pune, Campus Law Center, Delhi and a lot of other state universities. You need to apply to them individually. 

Thankyou.