When you sign up to do the course you will be given a password to access the adx material. Like desertopsguy said there is 500 ish questions.
The way I learnt them was to print off the questions with ONLY THE CORRECT ANSWER. By doing this I found that when I came to the test I recognised the answer without even fully reading the question.
I think it took about 25mins to do the test. (The record is about 19mins)
The best advise I can give you and it took me 2 attempts to pass the course is to study the adx like mad and put in for the test on the first few days because by week 3 the exams come thick and fast leaving no time for adx.
Hope this hels.