This page should help address your questions.
When taking an (ISC)² exam, can I skip a question and then go back to answer it?
What is Computer Adaptive Testing (CAT) and what exams use that test style?
Thanks for the detailed note and understood. I expected that I was able to skip questions and return them later as the official study book told me so. I had the CCSP exam yesterday, and I realized that it's impossible to skip&return questions and finally did not pass the exam - that was my fault. Do you have any plans to change this rule?