The importance if the lectures

The lectures along with the OT notes will provide more than sufficient knowledge to pass the exam, but as you rightly say MUST then be supplemented by an exam kit to give you the essential question practice to prepare you for the exam. There will be certain detailed points mostly in individual objective testing questions where you may not have the knowledge to be able to to complete an answer - but if you want a reference book to find the answers to these questions then you can if you wish also purchase a study manual.