Moving the media is simple. Just use your file browser app to copy the music, videos, pictures, etc, to the SD card. After you verify the files are there as you like them, you can delete the files from the internal storage.
Moving the apps is very problematic, to the point of not being worth it.
Your version of android needs to allow it.
The app needs to allow it.
Only some parts of the app can be moved.
Any updates to the app will move everything back to the internal storage.