If the script won’t show up in the Unity Editor, there is a good chance it has errors.
Daniel made another series of videos which may help aswell: https://www.youtube.com/watch?v=qN5lj9QT6Ws&list=PLp4vT3ssm5SUgZiG7dPaIfan1c0khdTKS
Scripting can be done in so many different ways and it really comes down to the application you need at the time. You can always have a look at the scripts we include with the integration to get some ideas. We also have plenty of info here: http://www.fmod.org/documentation/#content/generated/engine_new_unity/overview.html