The initial steps for creating a thing is to create a thing definition and an Application token. A thing is an instance of the thing definition. An Application token is required to connect the thing to the Management Portal. In the Management Portal, a thing is created after creating the thing definition. Below are the five different ways a thing may be created.
The thing definition is analogous to a class in object oriented programming. A class is a template for defining objects. It specifies the names and types of variables that exists in an object, as well as "methods"--procedures for operating on those variables. Similarly in the Management Portal a thing definition contains the attributes, functions and properties that exists in a thing.
An Application token is not required when a thing is created for a connection.