Home Page/Sample Page Menu

I've just discovered and started to customize the free Catch Box theme. Very simple yet very elegant. I've been able to find and utilize most of the options and customizable features I've been looking for but one. Is there a simple way to modify the menu bar underneath the header (not sure or it's technical name)? The default options are "Home" and "Sample Page". Any and all help greatly appreciated. Thank you John Goldsmith jgoldsmith@inbox.com