Because this is a fan patch, it requires a bit more work than buying a standard game. The general process involves patching the Japanese ISO of the game.
Looking for the English fan translation patch for Zero no Kiseki (Trails from Zero) on PSP? The complete patch is available from the team (now largely integrated into the official NIS America release, but the fan patch still exists for PSP). zero no kiseki english patch psp
Use a tool like xdeltaUI to apply the patch to your ISO. Because this is a fan patch, it requires