Exam

You should go with RS Agarwal for basics of aptitude and later you can practice Anil Nair books. These are the books for aptitude.

You can consider the below given points-
Analyze your strengths and weaknesses
Start reading
Set a reading target. Also, have a target list ready
Start working on your problem solving abilities
Extra focus on vocabulary.

Prepare the books published by S. Chand and A. S. Agarwal, it would be enough and go for the specific university’s website to get details regarding entrance exams. The top colleges offering BBA are Christ, Alliance, Madras Christian College, PSG, BHU, NMIMS, AIMS, MSRIM, Amity, LPU, etc.

If you have your Aadhar number, you can fill the form. It doesn't matter whether it’s updated or not. Government processes are always time taking. So, there’s nothing to worry about.

If you are asking for the expected rank vs score data, you have to wait for some more days (until the completion of exam). After that only mark vs rank can be predicted.