If you have a Pet - a cat, a dog, a stick insect - then you would be an Owner
So an instance of an Owner would be "Me", "You", "Him", "Her", "James", "Sarah", or ... anyone who might have a Pet.
A Pet would be the cat, dog, or stick insect that the specific Owner has: "My Cat", "Tiddles", "Bowser", "Sticky":
So I have a cat called Dij: I an an instance of the Owner class, Dij is an instance of the Pet class that has a relationship "Me.Pet = Dij":
Pet dij = new Pet (Pet.Class.Cat, "Dij", Pet.Colour.Black + Pet.Colour.White);
Owner me = new Owner("OriginalGriff", Dij);
But be very careful when you start playing with structs: they are not the same thing as a class, not at all - and if you don't understand the difference, you can make some very big mistakes that are difficult to track down and fix. This may help:
Using struct and class - what's that all about?[
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