Subdividing and combining articles
As articles tend to increase in size with time, it often becomes necessary to subdivide them. The ideal length for most articles is less than one "screenful", depending on the size of the intended viewer's screen, since this eliminates the need for vertical scrolling.
If you are creating a book or a lengthy document, it makes sense to break it up into chapters or subsections, using the Tree pane as an "outliner" to indicate the overall structure to you and maybe your readers.
On the other hand, if you are sending your document to others without TreePad, it may need to be in the form of a long plain text or rich text document, so you will need to combine your articles into one when finished.