Any *.md file within the Additional folder will be automatically copied to the final doc folder at the root of the project directory.
Each folder in this path becomes its own subsection within the ReadTheDocs YML manifest file. This only covers the base folder and all the *.md files within it (so no subfolders will be recognized). Each public function you have in this module will automatically be included in this manifest file under a 'Function' section and do not need to be specified (as they will be automatically generated by PlatyPS).