Here You have a great website where you can choose a sample of CB Cambridge exam.
You have a list of the exams. Choose the one you are going to take and have a look at a complete sample test.
It is useful to have a look at the video tutorial of each test.
Here you have the video explainig why is so convenient to take the Computer Based (CB) and which are the advantages of taking it.
I took this valuable information from Cambridge English Examinations ZH, Switzerland.
Hope you like it.