Therefore, it is necessary to design them ensuring easy search. Points for this are to create a table of contents
and stick to a fixed style for description of individual items. As an example of style, a text-type material on
spreadsheet software illustrated above is shown below. The style of this material is in titling all items in the same
way, describing the outline of each item, placing illustrations to the left while explanations to the right and giving
hints, etc.