PURPOSE: To improve the user interface and to shorten the processing time by dividing hierarchically the manual, etc., of a large document and storing these divided manuals into a section data set.

CONSTITUTION: A display 21 is provided together with a keyboard 22, a system processor 23, a manual processor 24, and a file device 25. In such a constitution, a manual document is divided into the hierarchical modules based on the table of contents, the index, and the component contents of the text. Then a table showing a structural position is added to each divided module, stored, and a designated module is called out of the text with a subcommand included in the text. Then the program contained in the manual document is carried out together with the command procedures and the system commands which are registered in a system library. In other words, a user selects the system command, the subcommand, and the procedure command out of the manual document. These selected commands are interactively carried out by a system. Thus the operability of the system is improved and the processing time is shortened.