CET BBA sample papers can be accessed online easily. Many websites host the past year papers too. Try to get hold of a good quality mock papers and simulate right examlike conditions at home and then try to give the exams in a definite time. This will help you cope up with the stress levels in the real exam. Try to get a book of sample papers. That would be beneficial too.
Here is a link which will help you with the exam pattern: https://bschool.careers360.com/articles/ggsipu-cet-bba-exam-pattern

Good luck!