There are several different ways to do that -- first, simply put it inside a form that points to where you want it to go:
This has the advantage of working even without javascript turned on.
Second, use a stand-alone button with javascript:
This however, will fail in browsers without JavaScript (Note: this is really bad practice -- you should be using event handlers, not inline code like this -- this is just the simplest way of illustrating the kind of thing I'm talking about.)
The third option is to style an actual link like a button:
This has the advantage of working everywhere and meaning what you most likely want it to mean.