For that particular code you need to look at some of the clues. First - the class is labeled as private - which means you are meant to put it inside some other class, probably an Activity. Second, it extends
Thread (which is a bad idea) and so you generally execute a thread by calling the Thread.start method. You do not see the start() method in the posted code because it exists in the Thread class, so you have to know how to use the Thread object, or look up the API for it. You would probably call the start() method from a button click or something - that part isn't clear, but would make sense. So if I were to use that class* I would do something like this:
* If I were to use it I would probably make it not extend Thread, but that is for another discussion...