Hey Sufian,
* How many hours I should spend study on the exam?
You should concentrate on for atleast 5 hours a day.Try preparing some notes for yourself when you read-on.Once you finish reading a chapter..read the summary/bullet points at the end of the chapter.read your notes and answer the mock questions.once you are done with the exam,review your answers.
* Should I study another book or tutorial other than HFSJ ?
In order to pass the exam, I think and believe that HFSJ is THE BEST.
* How he studied from HFSJ?
I assume this question is how to prepare for the exam.
* How many times he studied the book?
You can stop reading when you feel you are confident.
Hope this information helps.