How to implement eventhandlers

[Edward]

I've a Web Custom Control in C#. I've override the Render-
method to add 2 listboxes (lst1 and lst2) and 2 buttons
(btn1 and btn2). I also have a method to fill the
listboxes with data. I don't know how I can interact with
events from the listboxes and buttons. For example, what
must I do to handle the SelectedIndexChanged event of lst1
within the control?

Thanks in advance.
Edward