Create Parameters in a Revit Family

Hello everyone.

I’m reading about parameters, but I couldn’t find what I really wanted. I want to create parameters in a Family File (.rfa). I’ve found a lot about shared parameters or project parameters, but nothing on how to create a parameter. Is there any way to get and set the formulas of these parameters?
I’m a beginner in Dynamo and Python is still new for me, so I´m trying to look for a solution.

Thank you