Call to Action button over an image and/or slider

Hi all!

This may be something beyond my capabilities but here we go! (I am comfortable editing CSS, not PHP. I am using Bridge - CHILD and have FTP Access - if any of this helps)

I want to be able to add buttons over images and over sliders, similar to how my company supplier has done here (http://www.screencast.com/t/87fYnSzQ3C).

Is this possible?

Thanks in advance!

Mark