In order to install a new scene, just copy it to the SD card of your device, then launch the ScenePlayer app and add the new scene. Make sure to disconnect your device from your computer first because the app cannot read from the SD card while it is mounted as mass storage on your computer.
Regarding permissions: ScenePlayer requires
* android.permission.ACCESS_COARSE_LOCATION and
android.permission.WRITE_EXTERNAL_STORAGE for tagging and saving recordings;
* android.permission.RECORD_AUDIO for reading audio input from the microphone;
* android.permission.INTERNET for downloading new scenes from websites; and
* android.permission.READ_PHONE_STATE for silencing itself when a phone call comes in.
ScenePlayer is one of the sample apps that come with the free sound engine libpd. You can find the source code at https://github.com/libpd.
It uses additional capabilities of the Android device that are not used by RjDj or ScenePlayer apps (Bluetooth is an example) but it is still fully compatible with standard RjDj scenes.
Instruction for creating scenes for ScenePlayer Plus can be found at https://github.com/Nagasaki45/ScenePlayer-Plus/wiki
You can find the source code at https://github.com/Nagasaki45/ScenePlayer-Plus