First of all, you're going to need a few things. These are a memory stick, a reasonable knowledge of custom firmware's recovery menu, and CFW 5.50GEND3. Also, you'll need to download a plugin. Step one: Insert the Memory Stick Duo Pro into your computer using USB Connection or use of a adapter. Step two: Download this. Step three: Before you do this, backup your memory stick. Open up the program you have just downloaded. Now, where it says: "destination folder", select your PSP memory stick. Click install, and then wait for it to install on your PSP. Step four: Now that you have done that, go on the PSP's recovery menu (shut off your PSP, then hold the R button while turning it on). Step five: Go to "plugins" and select "cxmb.prx [VSH]" Step six: Get the theme that you want, and place it inside PSP -> THEME. Step seven: Install it by going to "Theme settings" and selecting it. Hope this helps.