I will like to write an application that can work with one or more project at a time. It does not quite matter what the projects are. The important thing is that each project will be saved into a bundle (eg. a directory with the extension bundle which is mostly treated as file in macOS).

Now my question is: what do I need to do in my app, or to the macOS system, so that when the user double clicks the bundle, my app is launched and the project contained in the bundle is opened?

I am sure all this is documented somewhere, and while I appreciate concrete examples, I will be more than happy to receive some pointers to the exact places where Apple has documented this.

Thank you very much in advance for all your help 🙂