For many exams, self-study is an option. However, EXIN recommends taking part in training for every exam. For most exams above foundation level, training is mandatory.
To find out if training is mandatory, go to the Certifications page and click on the preview for the exam you want to take. The requirements will be listed on this page.
To find the Preparation Guide, scroll down on the same page to the 'Downloads' tab. There you will be able to download the preparation guide. In the Preparation Guide, all the requirements are stated clearly.