It is as manches... said but they do separate groups into four different bowls. the first bowl has the best teams (Brazil, Argentina, Germany, England, France etc) these teams are the head of the group. they do so so that there are no two best teams in one group. then bowl 2 has good teams but not great and so on. they make about 8 groups of 4 teams each. That way they kind of make sure that all the better teams have more chances of advancing.