In order to access the grammar-vocabulary sections in one focus, you should have taken your comprehension test, at the end of your dialogue. At the beginning of each focus you have a dialogue that you have to listen twice. The aim is to get your ear used to the French pronounciation. At the end of the 2 listenings, you will be requested to answer a few questions about the dialogue.
In order to move to subsequent focuses, you should have answered the exercises at the end of each focus.