In our business world we could have a customer class and Bill Smith and Helen Jones would be instances of our customer class. In VB we define classes using Class Modules. Once the class is defined we can create objects based on the class module, with each object being an instance of this class. Class modules contain a declaration section, followed by a series of sub, function and property subroutines. These routines can only be called or used by creating an instance of the class.
All objects contain data about themselves.
For example, our animal class may be able to contain data for type, colour and number of legs. Furthermore, we could have many objects created from this animal class, each with its own type, colour and number of legs. Each of these objects would be an instance of the animal class. We store this data in instance variables. Every object we create has its own set of variables, even objects of the same class.