A basic thread is relatively simple in Java, using the Thread class.
The idea is you create a new Thread object and pass it an object that implements the Runnable interface:
Thread t = new Thread(runnableObject);
The Runnable interface has a single method you must implement called run(). This is the code that'll run in a separate thread. To execute it, you do start:
And that's all there is to it. Again, at a basic level. This should be enough, if all you need to do is run some calculations in a separate thread.