How do I find this information;

<div class="bg" style="position: absolute; left:0px; top:0px;

(top and left thing)
i know how to get the width and height thats easy.

there's a little section on that in A Simple DIV Overlay at the top of the help forum.

Just put random numbers. Like seriously play around. I would start with 200 for left. Then if you want to go more to the right, then make hte number higher. If you want to go more to the left make the number lower. For top start at 125. That will keep the ad unhidden. For top you should only go lower so that you don't cover the ad. So make the number higher to go lower.

Get it? I call that easy positioning.