No, it's better that you create your own project in whatever version of Xcode that you have, adapting accordingly. I think (from memory) that Xcode 12 onwards creates SwiftUI apps by default, so you would only need to create your new project and then:
Create a Swift file called DataModel and add the code I've given; Modify your new project's App file to add the @StateObject and .environmentObject lines I've given; Modify ContentView to be as I've described; Add your Plist entry as described.
Topic:
App & System Services
SubTopic:
Hardware
Tags: