This manual is designed to assist teachers in operating a school store as a classroom-laboratory for teaching marketing in the high school distributive education curriculum. The first part of the guide provides a rationale for competency-based instruction, introduces the cluster concept of organizing jobs in marketing and distributive education, gives suggestions on planning for specialized facilities for each job cluster, explains the project method for using the marketing and distributive education laboratory, and explores design of the classroom-laboratory facilities. The manual then describes the retailing laboratory (school store operation), providing a rationale and objectives, describing facilities and equipment, and discussing administrative considerations and instructional organization. Other sections cover using the laboratory as a project center and computers in the school store laboratory. Appendixes include facility layouts and space allocation sheets, school store accounts and inventory forms, a training plan for salespersons, and a job rating sheet. A list of resources is also included. (KC)