The hazard perception test is designed to determine your capability to identify possible hazards from an everyday act. You can pass the exam based on a computer analysis of the time it took you to react to different situations. Unlike the theory exam which is a Q and A test, and has right or wrong answers. You have to click as soon as you can when you see a potential hazard and again when it's a definite one. But avoid having too many clicks as this will mean a zero score for you.
Knowing what constitutes a hazard is worth keeping in mind while taking the test. Remember what you learned from your theory test and apply it when you take your hazard perception test. Review the road rules and practice as much as you can.
There are plenty of mock hazard perception tests you can find online. Doing a mock test will help you get a feel of what to expect from the hazard perception test. It might be confusing when you need to click on your mouse.
The sooner you click on a possible hazard the higher your score is. It can be frustrating when you fail on the first try, but go ahead and try again. You will start to understand the timing and what you should look out for. And it will make a huge difference in the actual test.