Board Thread:Support Requests - Getting Technical/@comment-29763315-20161106145456/@comment-24473195-20161106213222

I found it puzzling that you encounter the puzzle pieces often, so I looked into it.

Puzzle pieces appear in VisualEditor and RichText Editor  for different reasons. In the richtext editor it shows a place that contains a template, while in VisualEditor it will only appear in the editable area if either the template doesn't output anything or its output isn't visible.

As far as the editing templates is concerned, either the Help:Templates or Help:VisualEditor or perhaps even here will provide some more guidance. Note that the latter is somewhat different  because  Wikis here  use an  older version and  developers made some changes.