Install either the free or PPSSPP Gold version from the Google Play Store.
Attack on Titan (AOT) game for Android using the PPSSPP emulator WORK Download Game Attack On Titan Ppsspp Android
If the screen goes black but sound plays: Go back to Settings -> Graphics -> Change Backend from Vulkan to OpenGL. This fixes 90% of "not working" issues. Install either the free or PPSSPP Gold version