How should i study for SAT II World History Test?

found out (my parents signed me up for it) that im taking the world history SAT II test in about a little less than a month. They said since i just took the AP World History Exam (which freaked me out but i think i at least got a 3) and course that i should take it. I have the 2009 Barons 3rd edition prep book for it. But im not the best when it comes to studying. Anyway how many hours should i put into studying a day/week and what should i focus on and what should my goal be. Also can you reccomened me some practice tests or things i could use to study?