Step 1: Download and extract the GPsp folder and open it, then open the Install.zip
Step 2: you will see i already put the bios in there for you so now just place your wanted ROMS in the GBA/ROM folder (MAKE SURE TO USE STORE COMPRESSION)
Step 3: Exit the Install.zip and save if asked and locate your Content manager folders on your PC called /PS Vita/PSAVEDATA/XXXXXXXX (XXXXXX Being a bunch of random letters and numbers)
Step 4: Place the GPsp folder in this folder and then go to the PS Vita.
Step 5: load Content manager and connect to your PC and go to PC to PS Vita, then Applications, PSP/Other Savedata and you will see GPsp, Copy it to the Vita.
Step 6: Load Apache Overkill and load the VHBL by scrolling to High Scores and Press and hold the X button untill the VHBL loads.
Step 7: Using the Wmenu, scroll to the (..) at the top of the list and locate the SAVEDATA folder, open it and you will see GPsp, click on it and it will ask to install this Homebrew, click yes.
Step 8: Go back using the (..) again and go to GAME and presto, working Emulator.