Classes are objects with attributes and methods, to put it bluntly. The attributes are the variables associated with the class, and the methods are the functions associated with the class.
An example might illustrate what I mean:
"self" refers to the class' attribute. It's hard to explain, but just remember that it doesn't have to be specified when calling a function, only when defining it.
#First, we name the class, in this case "Person"
#An attribute of the Person class is the variable "name"
#This function returns the name of the "person"
#This function sets the name of the "person" to the new value that is given
def setname(self, name):
Examples of classes are "app" from appuifw, or "Sound" from audio etc.
For a more detailed tutorial about classes, go here.