The format of the exam is described and explained - after you've read the first pages of the book you will know what sections there are, how long each section takes and what you need to do in each section.
Read this e-book in any order you like, the chapters are completely independent, so you can skip a chapter and come back to it later. If you're good at listening, but need to work on your writing, you can go straight to the Writing chapter and study it first.
You can read this 80-page e-book in one day - in case you are time-poor and have found this website just days before your exam. It WILL help you in any case, just know this: the more you practice according to the tips in this book, the better your score will be in IELTS.