Ok, you can either copy your theme to a the &/usr/local/cpanel/base/frontend& placing the content inside a folder named after your theme, or if you want to make a themeball, upload your content, log into ssh and do the following:
# tar cvzf folder.tar.gz folder
changing folder to that of which your theme is called. That will zip it up. You can then either 1. Download that tar.gz and rename it .theme or, 2. you can copy that file to the frontend folder mentioned above and unzip it, by issueing the following command:
# tar xvzf folder.tar.gz
That should be all you need to do.