Custom node properties

When you click on the node, the properties of the pop-up node.
How do define the other attributes of a node

I’m not sure what you want to do. In general you can define your node template(s) to be as complicated as you like, showing as much information as you need to show. Using data Bindings keeps some of their properties in synch with model data properties.

If you haven’t read most of the pages of the Introduction, GoJS Introduction -- Northwoods Software, I recommend that you do so, because those pages cover most of the topics that every developer needs to know.