How to play background music through all activities using Kotlin?

How can I play a music file in the background through all activities by using Kotlin? I have looked everywhere but I only found solutions for Java not for Kotlin.

I tried using this function but I don't know how to use it:

fun playSound() {
    try {
        if (m.isPlaying()) {
            m.stop()
            m.release()
            //m = MediaPlayer()
        }

        val descriptor = assets.openFd("backgroundsound1.mp3")
        m.setDataSource(descriptor.fileDescriptor, descriptor.startOffset, descriptor.length)
        descriptor.close()

        m.prepare()
        m.setVolume(1f, 1f)
        m.setLooping(true)
        m.start()
    } catch (e: Exception) {
        e.printStackTrace()
    }

}

Here' code in kotlin code Play background music in all activities

class BackgroundSoundService : Service() {
    internal lateinit var player: MediaPlayer
    override fun onBind(arg0: Intent): IBinder? {

        return null
    }

    override fun onCreate() {
        super.onCreate()
       val afd = applicationContext.assets.openFd("backgroundsound1.wav") as AssetFileDescriptor
    val player = MediaPlayer()
    player.setDataSource(afd.fileDescriptor)
        player.isLooping = true // Set looping
        player.setVolume(100f, 100f)

    }

    override fun onStartCommand(intent: Intent, flags: Int, startId: Int): Int {
        player.start()
        return 1
    }

    override fun onStart(intent: Intent, startId: Int) {
        // TO DO
    }

    fun onUnBind(arg0: Intent): IBinder? {
        // TO DO Auto-generated method
        return null
    }

    fun onStop() {

    }

    fun onPause() {

    }

    override fun onDestroy() {
        player.stop()
        player.release()
    }

    override fun onLowMemory() {

    }

    companion object {
        private val TAG: String? = null
    }
}