Check out the House Rules and the initial announcement of the saga. I suggest that you read the whole thread of the announcement, as some questions were asked along the way and the process was informative.
Another suggestion would be not to begin creating a magus just yet. Get familiar with the saga first, its tone and its dynamics, before settling down on a concept. Then we can start discussing it in say, a month's time? Having played a little will help you avoid some pitfalls in character creation.