These templates are meant for use in {{Infobox river}}. They show the discharge route of rivers. For example, for the river Schwalm, which discharges into the Eder, the template {{PEder}} can be used. This gives the following output:
Usage: the template should be added to the "progression" field of Infobox river (for example: "| progression = {{PEder}}"). There are two types of templates: the ones starting with "P" and the ones starting with "R". The ones starting with "R" (e.g. {{REder}}) call the corresponding "P" template, and in addition they categorize the article into the correct tributaries category. In this case the category is Category:Tributaries of the Eder. For more information about these categories see {{Category doc drainage basin}}, or ask at Wikipedia talk:WikiProject Rivers.
Creating new templates: new template can be created similar to the existing ones. The codes of {{REder}} and its related templates are given below (template category <noinclude>[[Category:Weser basin succession templates]]</noinclude> omitted for clarity):