Hello,
Not sure what you are referring to in regards the use of plain white paper? No pens/pencils or paper are allowed during the exam. There is an online whiteboard for you to work out your math.
As for time management , the test has an on screen timer. So you need to do a little math in your head to figure out where you should be at what point. The exam was split roughly in half according to the number of questions. So about 120 minutes. The second half of the exam I finished in 1 hour and 15 minutes. So I completed the exam early by about 45 minutes. I did not review any of my questions for the second half. As I mentioned before if you second guess yourself you will change the answers that came instinctively. My overall score performance was Above Target for the exam.
Once you get past your nervousness it is just a matter of putting to use what you have studied. If you studied well you will not need to worry about time management.