Hi HostArkansas.
Nobody can take away fom you to learn sth. about CSS and XHTML.
To create a skin is not that quickly explained.
Changing an existing one is also not that easy.
If you open your style.css in your skin folder (blog/skins/YourSkin) with an appropriate editor (e.g. notepad++, free download: http://notepad-plus-plus.org/) you will see all the background images and colors.
After you copied your whole skin folder (in your case the "custom" skin folder) in the same directory and renamed it to your liking, you can start to make your changes.
For quick changes it is nice to have cPanel (make sure you open files with the right encoding ) on your server where you can quickly edit and see the results.
To change background grafics you should load the grafics down and change them with the help of a grafic programm (e.g. GIMP, free on the internet)
and load them up to your img folder.
Then change the name of the pics in your CSS.
To find colours codes you may like to use this: http://www.colorschemer.com/online.html .

Hope that gave you an idea about how to approach your undertaking.

noRiddle