I AM TOTALLY IN THE DARK :(

learn how javascript works.
find out what type of effect you want to achieve.
work towards that goal.

Start with

<script type="text/javascript><!--

//--></script>

and put all your codes in there. To find out how to write actual javascript, find a tutorial, try maybe hmm http://javascript.com/ or something they might have tutorials there.

Echo echo (http://www.echoecho.com/javascript.htm) has good tutorials.