A forum like this isn't the best place to learn something like mvc from scratch. Instead get a book on MVC and read through it, or at least look at some on-line tutorials.
http://www.asp.net/mvc[
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I'm going to assume you come from a webforms background, and if so you have to get your head around the different paradigm of MVC. Things like click-events etc were all abstractions around http that webforms provided for you in offer to give you an event-driven framework. With MVC you're using more bare-bones http, so a rough answer to your question is that your buttons will submit a form and the action of the form will be an action on one of your controllers. That is how you react to button clicks.
As I said though, you need to spend some time understanding the basics first and then things will become clear to you. There isn't really any one-to-one relation between doing things with webforms and doing them with MVC so questions like "how do I do <webforms feature=""> in MVC" will rarely produce a straight-forward answer as you should be doing things in an MVC way and forget about how you did them with webforms.
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