Construct relative and absolute file paths.
To a Relative Location...
In many situations, a relative file path is more robust than an absolute one. If a notebook is bundled with data or other files, a relative file path continues to work when the entire bundle is moved to a new location.
Without arguments, NotebookDirectory gives the path to the notebook that contains the evaluation:
Specify a path relative to this notebook’s directory with FileNameJoin:
Specify a path relative to this notebook’s directory’s parent directory using ParentDirectory: