Need to ad text in header

I have been working on customizing my wordpress the last few days, pretty much everything I have had problems with I have been able to find a solution… here’s something I cannot find..

I am using the default Kubrick theme and have altered the header to use my own image and not the default thing provided in the theme.

I am trying to add some text(will be google adsense) to go over the bottom of the header. I want it placed just above the bottom of the image and centered. I am new to css and tried to figure it out myself but cannot get it correct.

The link to my website is: https://www.igotitonclearance.com

If you can tell me what code to place and where to place it, that would be great!

If someone is able to help me, awesome!