Attributes? Properties? How do I add some instance-specific value to a trait?

Hi! Here is the situation: I have created a single trait, which makes the object that has it spin. I want the rotation speed to vary according to a parameter, so that I can give an object the trait at a certain speed, and then give it to another object at a different speed.

I saw that there is an “attributes” pannel", but it seems like I can just add names with no values. I tried adding the parameter as a custom property, and accessing it in the script through… whatever. But it doesn’t work either.

Edit: just found out there was an example with exactly what I needed!