He showed a button on a package called "Package Options" which is added by including a "packageView" in the package.manifest of the package - you can see the packageView in the docs here:
https://our.umbraco.com/Documentation/Extending/Property-Editors/package-manifest#sample-manifest
However it is not described further in the documentation. This view you link to is the "dashboard" that opens up, so you will have to create the UI yourself, and also use a way to persist the settings changes (this is where Callum used the KeyValueService)