Thank you for the provided screenshots.
Could you please tell me if you are trying to run the solution that is placed in the telerik.ui.for.aspnetmvc.2019.3.917.trial\wrappers\aspnetmvc\ Examples\VS2017 folder? I can see from the one of your screenshots that you have opened a TelerikMvcApp1 solution. If you have wish to use the Gantt code from the example project distributed with the trial package, then you will need to setup and connect to a database in order to be able to run the project with that configuration of the Gantt.
In the Kendo.Mvc.Examples project, you can navigate to the missing elements by marking the Model's name (e.g SampleEntities) and press F12. That would lead you to the implementation so that you can review it when setting it up in your solution.
As for the error you are getting in your index.cshtml, it looks as if you are missing some closing brackets when configuring the widget.
I hope I was helpful to you. Feel free to contact us if you have further questions.
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