To do LLB, you'll have to clear CLAT (Common Law Admission Test). Some of the best coaching out there to prepare for this exams are Career Launcher and Clat Possible. You can either opt for distance learning package or you can attend the coachings in person. They also offer huge discounts to meritorious students.

Now, if you don't want to join coaching or have some financial problems, you can easily prepare by watching the appropriate YouTube videos, which has became a common way to prepare nowadays. You can also freely watch lectures of awesome teachers on Unacademy as well.

Hope I have answered your question. All the best!