You can use the Writing with Ease (WWE) curriculum in a couple of ways.
The hardcover text The Complete Writer: Writing With Ease covers all four levels of WWE. If you want to generate your own student content (narrations, dictation, copy work, and so on), this text is all you need. This works great for families who wish to tailor the content to their preference. For example, some instructors want to focus the writing on their religious tradition, while others want to focus on history or stories or science. The Complete Writer can structure the program while you provide the content.
If, however, you want to have the student's assignments (narrations, dictation, copy work, and so on) prepared for you, purchase the Level 1-4 Workbooks. Each workbook includes both the teacher guide and the student material. In this case, The Complete Writer is helpful as a reference. It provides additional material that goes beyond the teacher guidance in the workbooks...but it is optional.