I am new for telerik controls, and i am too much confused about these controls how to use these controls in my asp.net site.
Assuming that you already have a licensed verison of the controls, this should get you started: RadControls for ASP.NET AJAX Step-by-Step tutorial.
Also, Telerik (in addition to StackOverflow) has a terrific community that will help answer questions on their forum.
Don't forget to check out their Documentation and Tutorials page.