How can I insert an adsense ad to the top of the html output file?

I've been banging my head on this for hours. I am trying to add an adsense ad to the top of the html output file for captivate 8. I want to place it right between the top border of the browser and the captivate project. I have played with the z-index tag but it just keeps getting covered by the captivate project, please help! i need a clean 100 px space betewwn browser and captivate project, thanks!