Hello jeewan thapa,
There is a know bug in RadCarousel that renders all elements inside a CarouselItem inactive. This bug has been fixed and the fix wll be included in our upcoming release. Actually the bug is only present in our default themes and if you define a custom style for CarouselItem it will not be a problem.
I am sending you a sample project that demontrates how you can add buttons to the carousel items, and how you can get the ID of a selected item.
All the best,
the Telerik team