Instance variable value as (varies)

I was looking at a template example and some instance variables have (varies) as value, I'm not sure how to set it.

Also I can't change the value for any of them, everytime I try it goes back to 0.

It shows "varies" when there are several instances selected and they have different values in the variable. If you select a single instance, you should be able to see its values and change them.