Please advise on changing categories from sidebar to horizontal menu

Hi,

Could anyone advise me how should I make my categories (there are only 4 of them) listed at the top of the page horizontaly instead of catgeroies being listed in the vertical menu in the sidebar?
I guess some css arrangements are also necessary, right?
Is this article right for me?
http://codex.wordpress.org/Creating_Horizontal_Menus

Thanks.