Thank you for writing.
That is correct. In order to add our form you need to add new RadForm to your project, or just make your Form inherit from RadForm:
Form1 : RadForm
To use the second approach, you need to make sure that Telerik.WinControls, Telerik.WinControls.UI and Telerik.Common assemblies are referenced in your project.
In regards to the themes, once you are using RadForm in your application, you can drag each of the predifined themes from the toolbox to the form and set the ThemeName
property of the form to this theme. Alternatively, after you drag the theme component to the form, you can set it as a theme for the whole application. More information regarding this matter can be found here: http://www.telerik.com/help/winforms/themes-using-default-themes.html
I hope this helps.
All the best,
the Telerik team