Please copy all the files from the folder “XML Files” to this folder:
MAC (Option 1)
MacintoshHD > Users:YourUserName > Library > Application Support > Microsoft:Office > User Templates > My Themes > Theme Colors
MAC (Option 2)
http://osxdaily.com/2011/07/22/access-user-library-folder-in-os-x-lion/
MAC (Option 3)
http://osxdaily.com/2011/07/04/show-library-directory-in-mac-os-x-lion/
If your PowerPoint was running during the process of copying files, it is necessary to completely close and restart it for changes to take effect.