The workbook essentially follows the textbook so that if a grammar structure is being studied in the textbook, the teacher can find exercises for the students to do in the workbook.  The workbook starts off fairly easy and become increasingly more difficult as the students make their way through it.  The workbook is packed full of exercises of all kinds: fill in the blanks, circle the correct word, write the correct spelling, put the words in the correct order to make a sentence, change a sentence from one type to another (for example, from positive to negative), answer the question, and ask a question from a given answer.  Each chapter (except Chapter One) ends with extra credit exercises where the students make their own sentences and questions.  Do as many exercises as you think the students can or have time to do.