[c#] How do I use updatePanel in asp.net without refreshing all page?

I want to design a website which contains sub-categories of a product in asp.net(c#). When I clicked a sub-category, then an image of product must be shown and the main page shouldn't be refreshed. How can I succeed it?

Please refer below Ajax overview:

http://msdn.microsoft.com/en-us/library/bb386454.aspx