Once you've completed the Google Form which analyses your current level of Google knowledge (take a look here, if you haven't completed it yet), you can use the training below to ensure that you are ready for the exam:
Comprehensive Training Materials
If you want the full suite of Google Training then take a look here. Be warned, this training is comprehensive and covers absolutely everything. It may take you quite some time to work your way through all of it. Nevertheless, it does contain some really good examples to get you thinking about how you could integrate Google into your lessons.