Yes, you'll be given the resource booklet as a class approximately 3-4 weeks before the exam and you'll most likely spend the lessons in the build up to the exam working through the pre-release, picking out the parts relevant to other units you've done, learning the new keywords. Some teachers will give their classes practice questions based on the resource booklet so that you can do a mock of the decision making exam - our teacher managed to get some of the predictions spot on!
You can annotate as much as you like on the copy given to you in class, but you cannot take this into the exam. In the exam, you'll be given a fresh new copy to use.
Don't worry though - they never go completely off topic. Follow the resource booklet and ensure that you've done a lot of revision and you'll be fine.