To get you started, you can download free sample tests here or do the compluter versions online. That �s the official website:

 

 www.cambridgeenglish.org/exams/advanced/preparation/

 

Other than that there are lots of testbanks (make sure they are for the version 2015 onwards since there were changes introduced to the format at that time) published by all the major publishing houses like Cambridge University Press (they publish past papers), Pearson-Longman etc.

If I can answer any of your questions/give you a hand - let me know