Hi could anyone help me with creating a really simple drop down css menu?

For example 1 main link and then when you hover over it a list of 3 appear below it.

I'm struggling to grasp the concept as ones i've seen around are really complicated.

Many thanks

Here is a very basic one:

     <a href='javascript:void(0)' id='firstLink'> 
         Link 1
            <li>Link 3</li>
li a ul{
li a{
li a:hover ul

If you want to see it in action here is the jsFiddle for it: http://jsfiddle.net/pLKSw/

Thanks for sharing the code.I am also new in it.It is helping me.