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The ability to reset/restart a tutorial will be available shortly in the Telerik Platform.
For now, please, refer to the workflow below.
Here are the links to the projects in their initial state:
You can clone the repository by creating a new AppBuilder Hybrid project and selecting Clone. Enter the address of the GitHub repository and create the project.
You can switch on the tutorials pane from the Getting Started > Interactive tutorials menu in the top right corner of your Platform account. Use the navigation at the top of the tutorial pane and switch the steps. Note that even that the steps are marked as completed, you can observe them from the drop-down menu in the tutorial pane.
I hope that this helps. Let me know if you have questions.