When logging on to the site you get a chance to make some adjustments.
Make sure your room is quiet and think about your surroundings (IE, what's in the background? Well lit? No barking dogs).
When clicking START, a lady will appear and ask a question, which is also written down. You will have maybe 5/10 seconds to think of an answer and then the recording starts.
Remember to look in the lens, not at yourself on the screen!
Don't use a mobile phone.
When you've finished recording, you have to click a button to stop. It will then ask you the next question.
Good luck!