Step 1: Download the file below as shown, IV0002-VBAM90000_00-SAMPLE0000000001.pkg and leave it on your Desktop. Now take a USB and plug it into your computer or PC.
Step 2: Copy the IV0002-VBAM90000_00-SAMPLE0000000001.pkg to the root of the USB, if you have any ROMS and for Game Boy Advance they will be in GBA format, Make a ROMS folder on the root of the USB and place your ROMS in here for now.
Step 3: Take the USB out of your PC and plug it into your PS3, on the PS3 scroll to the Game section on the XMB and select *Install Package Files and select IV0002-VBAM90000_00-SAMPLE0000000001.pkg and install it.
Step 4: After the installation completes, place your ROMS in the emulators folder. Open MultiMan and go to File Manager / MMOS, select PS3 Root and then Select the following directory: HDD0/game/VBAM90000/USRDIR/roms This is where you will place your GBA ROM files. Leave that aside and open another PS3 Root this time open your USB with this following directory: (USB in far right slot) USB000/roms select the ROMS individually by scrolling over and pressing X once and then hit O in the blue and COPY, Now go to the Emulator Directory and hit O and Paste.
Step 5: Once you've done that, exit MultiMan and get to the XMB. Scroll to where your VBAM Next is and boot it.
Step 6: Once loaded, Hit SELECT and open the options. Now scroll to PATH and hit X on the ROM DIR and now select the HDD0/game/VBAM90000/USRDIR/roms and it will always boot on that DIR.
Step 7: Reboot the Emulator and then load up a ROM and Enjoy.