Create a Drop-Down menu

I’m having a problem whilst trying to write a theme (my first one, so scary enough).

I’m trying to create a drop-down menu.

I get the code from various places online, but it shows all the sub-menus where they would be if you were hovering over the main menu item.

I’ve been searching online the past few days and have got nowhere.

I’m trying to figure out how to craete a drop-down menu that works in the usual way.

I’m using the following code:
<?php wp_page_menu('title_li=&sort_column=menu_order&show_home=1') ?>

However, this shows all the menu’s, including sub-menus, as you can see here:

http://blank.wp3.co

I just want to be able to create a menu that shows the first level until hovered over, then it will show the next level of that menu.

Level 1
About

Level 2
Test Page