You could start at the beginning and read to the end. If you are finding out about teaching English for the first time, then the resource will work as an introductory text to the subject.
2. Read a section
The contents page will direct you to different sections. In each section you will find units containing
10 ideas, tips, activities, questions or thoughts on a particular aspect of teaching. Some of the sections might not be immediately relevant to your context so you can leave these for later (when you might need them) and some sections will help you with immediate interests, concerns or questions.