Error Admin and Models

Can you please help I am getting this error after errors

The error message seems quite clear: you’re referring to field ‘slug’ in both Product and ProductAdmin, while ‘slug’ is an attribute of Category Model only.
I also noticed that str() is defined for the Meta class, while it should be a method of the Model class itself.

Can you please provide more details and if you can show me how to write that in a source code thanks