Step 1: Download the Theme Pack from below and extract the files.
Step 2: Plug in a USB and for ease of use make a folder on the root of the USB called Themes. Open that folder and place the Themes in this folder. Now unplug your USB and plug it into your CFW PS3.
Step 3: Open MultiMan or StealthMan, whatever on you have, and go to File Manager/mmOS. Once there open mmOS Root and you'll see USB001, Double Click the X Button on that and locate the Theme folder and open that, Press X once on the themes you want to copy and then hit CIRCLE, select copy.
Step 4: Open a new Window by opening mmOS Root again and go to the HDD00 and go to the Game golder, you will see a folder with the MultiMan logo on it, BLEUS..... open that folder and inside that folder go to themes, hit CIRCLE on the open Space and select Paste.
Step 5: On the File Manager Screen Select Games on what looks to be the Desktop of a Computer, you'll go back to the MultiMan XMB, once there go to Themes and apply them under MultiMan's Settings.