As the help in that document says...
Alternatively, use a change node to build this object.
set msg.payload to JSON then copy/paste that code in
This is about as basic as node-red gets. If you dont understand that then you need to spend a little time playing and learning. I strongly recommend watching this playlist: Node-RED Essentials. The videos are done by the developers of node-red. They're nice & short and to the point. You will understand a whole lot more in about 1 hour. A small investment for a lot of gain.
PS, this node looks FAR more difficult than zigbee2mqtt - there is none of this to do when you get zigbee2mqtt running.
