This video shows how to create a working folder for a KnotPlot project using a small helper application included in the KnotPlot distribution. This helper app is included with all version of KnotPlot for macOS starting from 26Feb18.
Note for users of macOS Catalina or later: Don't create your project directories inside your Desktop or Documents folders. If you do, KnotPlot might not be able to access them the contents of those folders (due to security concerns). Create your project folders any other place and you should be fine.
To see how to create a KnotPlot project folder on Windows see the video • Create a Folder for a KnotPlot Project