If you're using a PDF or older version, consider upgrading to the revised 2023 edition. It’s much "fresher" and the digital tools make self-study significantly easier.
: It covers all four primary language skills— reading, writing, speaking, and listening —integrated into eight or nine thematic chapters.
Because De Sprong is a popular course, many students sell their used workbooks for €15-€25. Ask the seller if the workbook has been written in. If it is untouched (or erased), you are getting a cheap, legal physical copy.