Assuming you have found a clean Double Dragon Neo Geo APK file and have enabled “Install from Unknown Sources” in your Android settings, follow this generic guide:
An APK file for this game would typically be a ROM file (the game data) packaged with an emulator app (like Neo.emu, MAME4droid, or similar) that runs on Android devices. Downloading ROMs of commercial games you do not own is generally considered copyright infringement. double dragon neo geo apk