Studying the TOGAF 9.2 standard found on The Open Group website is enough to pass for the exam, but my study routine usually always involves a physical book and some CBT videos. I found the study guides to be very beneficial primarily due to the extra examples, the practice questions and exams which was key for me in building up my confidence level. I always find CBT videos helpful especially as background noise when I am doing something else around the house, in the case of TOGAF it was nice to hear someone explain the couple of concepts I initially had trouble grasping or visualizing. Plus the courses from Udemy were not very expensive when I had purchased them so for the cost I found them well worth it.