Hello Sukhad

For BBA exam 

Four things are of importance 

1 general awareness

2 english

3 quantitative aptitude

4 reasoning

What important is you must have good vocabulary.You must practice forComprehensions problems for english. Practice regarding the analytical reasoning which could be marks scoring for some and the most difficult for the other. One must know regarding the basics as no one over there is going to ask about the method or the steps involved while solving. And you must have good hold on mathematics. Chapters like permutation combination , probability , algebra , co-ordinate geometry, etc. are important start practicing from NCERT. You may buy a book for current affairs and general knowledge or you can look for the websites that have a lots of information regarding the awareness whether it is static or general. If you are much confused and have less time for the entrance exam then you may look put for the institutes that provides express courses for fast completion of the syllabus so that the candidate must know about the basics of the questions that he/she is going to face on the pen paper/computer based exam. Most important is get good marks in 12 boards .