Please use How to use code fences when posting code, logs, and config files.
It’s really helpful to link to these so we can get a better idea of what you are trying to do. There are tons of incorrect tutorials out there too.
I don’t think you can have that comment in the definition of the newArrayList. Delete that //... add all your... line.
Do you have the MQTT Action installed? It’s separately installable.
Without proper formatting I’m, not sure I can help much more.