Please advice if we need to take complete exams for CPA at one time or if we can take exams separately for these 4 subjects since the exams are happening 04 times a year.

Dear Mr. Adham

Yes, you can take 4 exams separately. 
All I request you to pay us a visit on any Friday morning between 9 am to 12 or 2 pm to 5 pm. if you come you can meet our trainer even you can sit in the ongoing CPA training class, then you can get an overall idea about the CPA course, registration process and examination pattern.
if you want to clear all your doubts, please visit our Institute.

Regards
Business Development Executive