New to C# and am working through Beginning C# 2012 Programming. There doesn't appear to be a specific forum for it. Anyway, I'm having trouble understanding Ch. 8 "Introduction to Object Oriented Programming". I figure this is a pretty important topic, but I'm not quite grasping when you would use the various elements (Struct, Class, Interfaces,etc.) I've reread the chapter 3 times and sorta get what is going on, but have no idea where and how I would use them. Is that something that is explained further in the book or do I need to totally understand this section before I move on?

This is what I think Ch 8 is trying to say:

class can be
public or internal = access types
abstract or sealed = inheritance types
used to group object and it's common functions
reference type

interface can be
public or internal = access types
abstract or sealed = inheritance types
used to implement functions that could be shared among otherwise dissimilar objects.

struct
similar to class except it is a value type not reference.

Am I on track?