I see that the game was made with Godot. For the coconut, you could create an AudioStreamPlayer node (as a child) for it and then whenever the coconut changes direction (whichever function does it) you can play the sound using AudioStreamPlayer.play(). Just make sure the script that controls the coconut has a reference to the stream player so that the play() function can be used.
For playing the sound when points update, you can do a similar process. Create another AudioStreamPlayer node for the node containing the script and in the function where the score changes, call the play() function.
I haven't seen the code for the tutorial you followed so I'm not sure how exactly it's set up, but adding sound is quite simple. Hope this helps!