Please read the header info in main.c

Place the EBOOT.PBP into the 'Files' folder, rename that folder to whatever you want and put it in PSP/GAME(150). All the flashed files are .3d images. Here's a list:

bg2.3d = Flash1 background
bg.3d = flash0 01-12.bmp
font.3d = ltn0.pgf 
htmlviewer.3d = Visit PSP3D via the online instruction manuals. I forget which file.
topmenu.3d = Topmenu_plugin.rco (Pretty crap ATM, made when the first icon hack came out) - 3.03 OE-C only.
update.3d = TUW's Rebooter PRX.
Waves.3d = XMB waves.

Have fun.