The document discusses the importance of instructional guides when selling products. It provides several reasons why instructional guides are important, including making the explanations comprehensible for customers and clarifying the operational procedures. The document also discusses writing major points in simple sentences with illustrations to make the information easily understandable. It explains reasons for studying the instructional manual before using a product, such as understanding operational procedures and directions. Finally, the document provides an example of how an instructional guide could help a customer solve a problem by clearly describing procedures and including illustrations.