Implementing the processAudio method is necessary for the code to to run the patch. If a patch class doesn't implement processAudio then it must inherit a class that does; in fact, it is the only method you have to implement. The actual implementation, instantiation of buffers et c, depends on whether you run the patch on the pedal or in OwlSim. Normally you wouldn't need to access any of that. What is it you would like to do?
If you need a buffer for your patch you can create one with createMemoryBuffer() and use it e.g. for delays or fft's.
If on the other hand you want to run OWL patches yourself you will want to look at either OwlWare (ARM firmware) or OwlSim (linux/mac/win software) to see how we do it.