The images (icons/button elements, etc.) in CCP are located in a Folder called Complete Control Program. Try to locate that in your computer. Then, within that is a series of subfolders. Open MX-980, then Images.

This is where you would then have to create a new "Theme" folder (Alpha 2, for example, or Fusion) You create this new folder by copying the folder that you found online and copying and/or renaming its contents to your liking and placing it in the images folder.

There are many threads here that show you step by step on how to do that.

As far as backgrounds and wallpapers, you can just insert any image you want. You just have to make sure that the image size of the picture is 240 x 320 pixels, which can be created or re-sized using the tools found here, as well.

Be careful to always practice loading your new graphics into a "copy" of a folder first. You don't want to accidentally tamper with the default files with CCP. Might be better to just create new folders and themes as you make your modifications rather than running the risk of messing up the existing ones.