When it says a forty yard field goal, just remember that the endzone counts as ten yards. All you need to do is set yourself up on or behind the thirty yard line and kick a field goal. The closer you are to the thirty, the easier it will be (just make sure you are beind it).
*I was told the set-up for the kick is also seven yards. This means you should try and get as close to the twenty-three to make it as easy as possible.