I enjoyed this tutorial, but it could really use an update for XCode 11. Some of the UI has changed in ways that could really trip beginners up. For example, the Object Library is no longer in the lower right, but is accessed by clicking the new [+] icon in the menu bar. Cocoa app is now just “App”. It shouldn’t take that much effort, just some new screenshots and some text edits, but I imagine a refresh would add a lot of value for beginner readers.