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Thanks for your input. You are right that the sample apps are well explained in dedicated articles. I am guessing that Hoang is also referring to the Interactive Tutorials available in the Telerik Platform (from the Getting Started > Interactive Tutorials
Yes, here are the finished tutorials which can be used for reference. Just to mention that you can switch between the steps from the drop-down menu with the step number in the top of the tutorial pane. Thus you will be able to review previous steps even if they are marked as completed.
Here is the list with the tutorials:
You can clone the apps directly in your preferred AppBuilder client and explore the code. Here are the links for cloning them directly under your Telerik Platform account:
Please, let me know if you have questions.