In order to run your app on an Apple Watch, you'll need to have Xcode installed.
Enter edit mode in the quiz creation area by clicking the button that looks like a pencil at the top center of the page. When in edit mode click the "Export" button on the bottom right of the screen. The export button will display a success box which will toggle choices of which platform you can download for. In this case, choose SwiftUI (iOS).
Check out the video below and please let us know if you have any questions!