It really is just common sense. I tried to find stuff to read before mine, but couldn't find much.
Went along and was really nervous because I wasn't sure what to expect.
As Crofterloon says, there is a session to start with so that you can familiarise yourself with the computer and then you go through the multiple choice questions.
Didn't take very long at all. The 'instructor' said that some people do fail...but usually because they aren't used to computers rather than getting questions wrong......or people that aren't familiar with animals - not sure why they would want to take the test though.
Good luck with yours....I'm sure you will do well.