Im pretty much of a nub....

I want to create a menu (navigation bar) on the left side of the screen on a normal html homepage, like most webpages have. Some of the menus, like a "photo" section have more than on subsection. When entering the page only the main sections shouls appear in the bar (ie: home, photos, contact etc.) When clickde on photos the menu should expand vertically. When another menu point, such as "home" is clicked, then "photos" should contract. Is this whithin the makeable or is it very complicated. Ive searched in all of the sample sections...and couldnt find much